Any advice on this unfortunate situation?

I am currently watching two dogs, one is leash reactive. Today when we went out for our walk, the neighbors dog came up to us, off leash, and they started fighting. When I told the owner of the dogs I am watching, she told me she knows the dog that approached us and was surprised that it had caused an incident and that it “probably would have been better” if I had let the reactive dog off it’s leash, because that’s what they usually do. She did say that she was sorry it happened, but she almost seemed to be insinuating that it was my fault somehow and that I needed to relax about the whole thing. She still wants me to take them off leash at the park and throw the ball for them. She said “the dog park is much easier because he is happy off leash”. I am supposed to watch them again in October. I told her maybe we can all go to the park together before then so I can get a sense of how he is, but now I am having second thoughts about even watching them again. Not only do I not trust that the neighbor will keep her dogs secure, I feel that the owner of these dogs does not understand the severity of the situation, and I’m feeling like I simply do not want to take her or anyone else’s dogs off leash anywhere as it is too risky. I don’t know if I should try to talk this out with her, or just tell her I am not interested in watching them again. Am I over reacting? What would you do?