[soulfuldog]

Just tried squeezing the bezel on mine and it does nothing (it does make a creaking noise on the left side of it though, so I'm not keen to squeeze it too hard!). In saying that, if you have tried it on your Mum's PW and can only replicate a page turn by squeezing it pretty hard and only sometimes, it sounds more likely that she is accidentally brushing the screen with her thumb/finger while holding it. I just tried it out and if your thumb is anywhere near the edge of the bezel, it does only take a very light touch with part of your thumb to turn a page.

Why not give her your PW to try, if the same thing happens with it, its clearly an accidental page turn and nothing wrong with the PW?

Edited to add: Otherwise, I'm sure if you contact Amazon they'd replace it for you.