Nah, I think there may have been inspiration from Huck Finn instead. Sorry, I don't know what I'm allowed to speculate on and what not; I'm new. Please edit as appropriate for me mods, thanks, lol.
Early on in the case I thought I'd read that the stepmother had said about KH that he was no Huck Finn. And I thought to myself what an incredibly odd thing to say. And it bugged me. Not he wasn't adventurous, or he was a homebody, but that direct and somewhat derogatory comparison. As if she admired Huck Finn and KH wasn't any of that.
And it had to be fresh, stuff wings in and out of our verbal vernaculars. I grew more curious. So I googled Huck Finn traits and this thing, that may or may not be relevant, jumped out at me too especially with the internet buzz about the pings at sauvie island and how maybe KH really is alive and being held somewhere:
"Huck's ingenuity is shown throughout his clever actions. His decision to make his escape on the canoe look like a murder to hide his tracks is just one example, "And they'll follow that meal track to the lake and go browsing down the creek that leads out of it to find the robbers that killed me and took the things. They won't ever hunt the river for anything but my dead carcass. They'll soon get tired of that, and won't bother no more about me." (This idea continues as he decides to dress up as a girl to gain information. Although this idea doesn't fully succeed because he is found out, it is an excellent plan, which also reviles his ingenuity.")
http://www.123helpme.com/view.asp?id=15704
Didn't the step mom help kids with their reading at the school and have a degree in that too? She could probably be very familiar with this in addition to just making the comparison between KH and Huck Finn.
Hide or pretend to hide the body in water - check
Red Herrings - mebbe the pings were that, mebbe it was a layered plan if she was involved in it - plan 1 - blame the school/situational scenario; if that fails then plan 2 - make sure the phone is pinging somewhere I'm not, create an illusion, a red herring as a backup plan - if they're going to look have them look in the wrong place so i won't get caught - or as Huck Finn says "And they'll follow that meal track to the lake and go browsing down the creek that leads out of it to find the robbers that killed me and took the things. They won't ever hunt the river for anything but my dead carcass. They'll soon get tired of that, and won't bother no more about me."
And now that development today with DY's saying KH is still alive it also goes back to that Huck Finn plan. Goofy as all heck but it keeps ringing true as events commence.
IMO CSI shirt may be because she thinks she's so smart in planning this, if indeed that's what transpired and I can't know that. CSI shirt - a taunt and a red herring, look at CSI shows, but I'm doing Huck Finn.
I hope I got across what I meant without saying the wrong thing.