Cheryl; Fraggles' body language does not in anyway suggest that this was light punishment. Also, she did not bite, or harm in anyway, the cleaner, so it was not a pain reaction. Fraggles was just having fun, from the sounds of it.
Also, rabbits can defend themselves, but only to a certain degree. Reuben attacks my broom when I sweep, but just one good hit and he'd be running; there's no way he could stand up to me if I started hitting him.
I think you are morally right withholding the pay check; you did after all have to pay for a vet visit, which if you had paid her the check, I think you should have asked that she pay for. Evens out.
Also, I have a hormonal rat who is very sweet and cuddly; he even gives me kisses on my face no problem! But sometimes, because his hormones make him grumpy, he bites. Hard. I have a couple of scars on my fingers, the bites are so deep. I mean, we all know how deep rodent bites can be! Sometimes I have been left unable to use a finger, but the most I have ever done was swear at him. Sometimes I feel like I could throw him across the room but you know what? After I have put something over the bite, I pick him up, and he gives me kisses. Sometimes with my blood smeared over his mouth.
I have never hurt him, or come close to it, even with severe pain; the last bite sliced my hand open through to the fat cells. Nice one, Dodge.