I've been thinking a lot about such problems lately and have to say that my reservations regarding premeditation may have been premature. Initially I had ruled out that possibility because a document prepared in advance would, in all likelihood, have been printed out or typed, rather than written by hand. And why would he have wanted to use paper taken from a notepad in his own home?
However, thinking more deeply about the various possibilities has led me to realize that a printed note is not necessarily the best way to disguise one's identity. John would certainly not have wanted to use a printer from his home or office. Every print head has unique wear marks that enable forensic examiners to identify the printer used to produce any document. If the note could be traced to a printer associated with him, that would be powerful evidence indeed. And if he had made an effort to find a printer not associated directly with him, that too could have been a problem, as the owner of the printer might later have recognized the strange man with the strange request and reported the incident.
It might therefore have occurred to him that, if only he could disguise his hand convincingly enough, the best way to go would be to actually write it out the old fashioned way, with a pen. Perhaps that's when he hit on the idea of tracing (or copying) a computer font. If he did it carefully enough, then it might well fool the "experts" -- moreover, a document printed in a hand that looked so different from his would point away from him to the hand of some unknown "intruder."
There remains, of course, the question of why he'd have used paper from his own home rather than just go out and buy some. I think it likely he might not have given much thought to the possibility that the note could be traced back to Patsy's notepad. We now tend to take this discovery for granted, but in fact it was a very lucky break that one of the investigators happened to notice the match. John would have needed paper. He might not have wanted to risk buying some, since the clerk might later recognize him. The simplest thing, as far as he was concerned, might well have been to simply appropriate Patsy's pad. It was a standard notepad of a type that can be found just about anywhere.
One more question remains. I have always maintained that John could have destroyed the note before calling the police, claiming the kidnappers wanted it returned. If that had been part of his plan, however, then the simplest thing would have been to print the note rather than taking all the trouble to write it by hand. Now I believe that this might not have been John's plan after all. He might have been confident enough that the computer font he'd copied would have fooled the investigators, so handing them the note might not have been a problem for him and, if they could not figure out who wrote it, then it would be added evidence for the existence of "the intruder." (And of course his confidence was justified, since he was in fact ruled out.)
I must at this point consider the possibility that the note could have been prepared in advance, not by John, but by a real intruder. To this end, I'll simply repeat what I wrote in my earlier post:
Of course, someone close to the Ramseys could have taken the notepad with him, written the note on it, and then returned. Which sounds good at first, until one asks oneself: why? The only reason for doing that would be to make it look as though one of the Ramseys wrote it, but that would work only if the intruder actually forged John or Patsy's hand. But there is no evidence of that, and none of the document examiners on either side of the fence ever suggested the note could be a deliberate forgery. A "ransom" note written by an intruder, or one that looks like it was written by an intruder, could be seen as intruder evidence, so if the intruder were trying to set John or Patsy up, why would he leave a note in his own hand? Well, obviously, he wouldn't. So if the note was written ahead of time, it could not have been written by an intruder.Now let's see if it's possible to recreate John's actions, assuming that he did in fact premeditate the murder and write the note in advance:
First of all, it's not likely he would have made his decision very far in advance, because JonBenet could have exposed him at any time. It's possible the decision was made as late as the day before Christmas or Christmas day. John could have spent time online researching various kidnap scenarios and kidnap notes, copying and pasting certain details, such as "Don't grow a brain" or "any deviation of my instructions" or "if we catch you talking to a stray dog, she dies," etc. Once the note was composed on his laptop he'd have been ready for the next step: getting it on paper. Oh, and by the way, a word processor such as MS Word will normally copy a backup of your document to your hard drive -- however, that is a feature that can be disabled, which John would probably have done. He could also have saved it and subsequently erased it in such a way as to make it unrecoverable.
It's possible that his trip to the airport on Christmas day (which seems like an odd thing to do on Christmas) could have been a cover for his going somewhere surreptitiously to pen the note. He could have taken the notepad with him to the airport or anywhere else where he could work in private. He'd have opened out his laptop, placed a sheet of paper over it and simply traced, line by line, the word processor layout, from the display. Or else just copied it, being careful to reproduce the layout as precisely as possible. For the details of how he could have done this, see this post.
When he was done, he'd have kept the three completed sheets hidden inside the pad, then returned to the house and hidden the pad in a drawer. It's also possible that, at the White's party, he could have managed to drug Patsy and Burke's drinks to make sure they'd sleep soundly.
That night, after everyone had gone to bed, he would have awakened JonBenet, distracted her with a pineapple treat, and then assaulted her. He would then have wrapped the body in the blanket and hidden it away carefully in the windowless room, in case Patsy went looking for her after finding the note. He would also have done at least some staging in the basement, including breaking the glass in the window pane. Finally, he'd have retrieved the notepad, extracted the three sheets and placed them on the staircase where he knew Patsy would later find them. This would explain why those sheets were never folded or creased. They would have been kept in pristine condition inside the pad until ready to be displayed.
By that time it would have been close to wakeup time, so he would have headed to the shower, the sound of which awakened Patsy.
I'm still not completely sure it happened that way. It's still possible the note was composed and written down after the murder. But as I now see it, the possibility of premeditation does seem more likely than before.