I realised a few months ago that, of the couple of students I teach, most of the "bad posture" points go to owners of smaller, more "ergonomic" basses? Those with more traditional P and J basses actually have to work that bit harder and seem to get in better habits quicker!
Now, I'm not a "fender was right" believer in general - neck heavy basses are a pain, so are over-heavy ones.....I like headless...but I was surprised by my own observation.