73 in a year is impressive, I wouldn't have credited them with that kind of productivty... and given how daft and angry our two I shudder to think of dozens of rabbits gently walking into walls and bumping their heads against the door.
You have to question the kind of idiot who could overlook that little detail. I can understand maybe one accident after getting them from the petshop, you can occasionally be unlucky with guessing the age or not check for their gender (quite difficult until they reach sexual maturity, especially if like friend, you have a psychotic reaction to it) for a few days and BAM!... rabbity sex. Puberty lasts about 30 seconds for a bunny.
But after that, no excuse. The guy should at least be banned from keeping rabbits, if no other animal because he obviously doesn't have a clue.