If you mean playing pieces further on in the book, when they haven't mastered or sometimes even grasped the technique in the one we're dong, then yes I have experienced it!
I have a student in his late 20s/early 30s who does this every lesson! And then he sometimes says "oh, I didn't look at these pieces at all because I was concentrating on this one that looked really exciting, so I can't play the others" - well can you play the one you've been playing all week thats at the back of the book? "no cos it's really really hard!"
I addressed the situation after a few lessons by explaining that whilst we play enjoyable pieces as well, we also play some pieces so he can learn a particular aspect of technique, etc. I told him that he can go on to play harder things if he wants, but I'm not going to listen to the pieces he's chosen by himself until he can play everything that we are working on in the lesson. That means that he has to practice what I've given him, because otherwise he would turn up at the lesson with nothing to play and would go backward - which he did when I first confronted him with this - we spent the entire lessons going over what we had done the last lesson, but which he hadn't even glanced at during the week. The lesson after that, he came and had practiced everything and had made progress, so I said I would listen to the other pieces he'd been practising that I hadn't chosen. Its working so far!
He is my most extreme culprit, but I have others who follow a similar theme and the trick I find is to keep the pieces more varied for them than I usually do. I tend to use a book of pieces that are slightly too easy for them, alongside the "tutor book" (or whatever big/exam piece we're working on). This means that we run through these pieces quite quickly and they feel achievement - which is true, as it helps with their reading skills and as the notes are relatively simple for them, things like dynamics and articulation can be focused on more.