I don't know what I'd do in that position!!! If a neighbours cat was unneutered I think I might even be tempted to accidentally take them to the vets!!!!
That sounds terrible doesn't it!!!! I think I'm probably just an interfeering busy body!
I remember a few years ago there was a big story, (front page and everything!) with our local newspaper, about several cats on a local council estate who mysteriously got neutered. Resulting in several 'very angry!!!'(????) owners. They were so mad about their cat being neutered
Cue photo of council estate Mum, hands on hips with mean stare quoting, "If I ever get my 'ands on who did dis' to my cat.....!" But no cats in photo's...???? Probably got rid of them for another money making machine.