Yeah, I have no issue with having to go in and get into whatever I want to read prior to putting it in a baggie then just using the hardware pageflip buttons, so a PRS+ option to toggle touch on/off - particularly from within a book (since I'm not sure you'd be able to open the book at all without the touchscreen) would be extremely welcome.
I will have to try the trick of just adding a bit of air to the baggie so the bag doesn't touch the screen for now and see if I can get that working myself in the meantime. Otherwise I'll have to just keep my old reader around for that and keep it synced up (which isn't that big of a deal truly, just enough of a hassle to make me want a solution for the 350)