The rival university one seems like a solid prank. The user I replied to did not make it sound like the intent was to be funny.
> whenever I don't feel like putting my own email or phone number I just put his
This sounds more like malice than well thought out humor. If I found out someone I knew and respected was using my primary contact information for spam emails at <insert random pet supply store or random restaurants' rewards programs here> I would definitely consider not talking to that person much any more. The rival university one however I would let slide because the intent from you is obviously different.
> whenever I don't feel like putting my own email or phone number I just put his
This sounds more like malice than well thought out humor. If I found out someone I knew and respected was using my primary contact information for spam emails at <insert random pet supply store or random restaurants' rewards programs here> I would definitely consider not talking to that person much any more. The rival university one however I would let slide because the intent from you is obviously different.