This is true, the adhesive stick side, how much do they differ from vendor to vendor, indeed if it does come off the screen and tends to want to stick to the screen, that's bad. I guess I've been very particular to Nokia screen protectors, both my 5230 and n900 have the factory protector (as far as I know) and the "stickyness" is just right, at least it doesn't come off and stay on the screen.

But maybe too weak because they don't stick forever