I can't imagine ever regretting trying to do something about a situation that you discovered that could be dangerous to your own family (Inc pets) and others.
If you don't at least try to improve it then you may regret it later.
Not that them paying $200 will necessarily change how they treat their dog, but it's a step toward awareness and starts more discussion about the problem.
Of course there may be a lot of details/past experiences with those people that I'm not aware of so take it with a grain of salt. I just think that's there is a better option than shrugging it off.
If you don't at least try to improve it then you may regret it later.
Not that them paying $200 will necessarily change how they treat their dog, but it's a step toward awareness and starts more discussion about the problem.
Of course there may be a lot of details/past experiences with those people that I'm not aware of so take it with a grain of salt. I just think that's there is a better option than shrugging it off.