I'm not going to let the owner influence me into donating for a dog's cancer treatment
Why are you so against it?
I should freely make my own decisions.
You don't have to donate if don't have any money to give. Don't let them guilt you in donating.
RIght? Sure, if I had the money to but I don't right now. And it's not my dog so I shouldn't be stretching myself to help/
Those are the exact reasons you shouldn't worry about it. You don't have to donate money to something you don't believe in or can't afford. It just doesn't make sense to do so.