In another story, the cat owner says the teacher never mentioned that the cat was causing a problem. That doesn’t look good at all for the teacher.
What's she gonna say? "Oh, she told me a hunnert times to keep my cat off her property."
If your cat is out and about you can bet that it is on other peoples property where it does not belong. That is a pretty simple assumption. I keep my dogs at home and secured at all times. That is my responsibility as a pet owner. I can not say I do not have this responsibility just because no one has told me my unsecured dogs are causing them a problem.
I do not want to hear the crap about cats just being cats. If you chose to have a python as a pet it has to be contained so it doesn't go next door and act like a "python." There is no difference. If you have a pet it is your responsibility to restrain and contain it so it does not violate other peoples property or rights.