One thing I've noticed after watching some TNG episodes is that crew members can enter their fellow officers' quarters without permission. The episodes "The Outrageous Okona" and "Measure of a Man" come to mind. It's almost as if people aboard the Enterprise have no expectation of privacy. Is this ever touched upon? I mean, do the doors to quarters not have locks? Do crew really trust each other to the point that they keep their quarters unlocked? Or do senior officers have some sort of ability to override security?