I detest free ranging cats and their idiot owners.
I bought my own cat trap and I've disappeared 2 cats so far. I don't warn their owners that I've got a trap, nor do I warn them that their cats will never come back if I catch them, and I do not involve the council rangers, did that once, the damb cat came back that day and I was abused by the owners for having the gaul to trap their free ranging murderous cat , that I've been complaining about for months (was exterminating the wild water skinks, frogs, garden skinks, and parrots and doves , and attacking the little possums etc that I was trying to encourage into my yard by feeding them) , their cat was not registered, not microchipped and not collared (ie illegal) as well as being a wildlife predator and a pest.
My advice is buy your own trap, don't tell the owners of the cat/s of your plans, and just deal with the cats quietly and permanently
IMO if a pet comes onto your premises and harms or damages your property or your pets or any wildlife on your premises, it's far game and your can use amy means at your disposal to deal with it. It also indicates a total lack of respect you by the offending pets owners.