I'd love to hear more about this academic dishonesty. I've been disconnected from academia for a long time.
For me, I specifically make a lot of my work public to avoid someone else claiming sole invention rights--as I have reasonable public proof of prior art. Though to this day this has never happened, and people have always given my projects more than appropriate credit without even having to ask.
Having served as a TA, I can assure you some students will seek out anything tangentially related and make few if any modifications to the project. This isn't just a case of reused projects, too. A lot of times our assignments would be open-ended within a framework (e.g., create a game that uses the minimax algorithm). Things like that. And naturally they seek out anyone that had taken the class previously.
For me, I specifically make a lot of my work public to avoid someone else claiming sole invention rights--as I have reasonable public proof of prior art. Though to this day this has never happened, and people have always given my projects more than appropriate credit without even having to ask.