in the UK garden centres sell a product made from lion dung ,
deters the cats from using your garden
I understand that some cats don't like to be inside, and in no way is this reply an 'attack', but rather an observation on the situation- but there are other solutions than solving your problem (cat making mess in your house/acting out) and creating a problem for someone else (cat using their backyard as a toilet/harassing their dog-yep, we have a neighbourhood cat which will sit in our yard and try and attack our Corgi if he goes near it). One such solution is an outdoor cat run. The cat gets its outside space, but can't wander onto other people's yards. Whilst this might not be a convenient solution for everyone I hope that in the future there will be rules governing cats freedom to wander, and that when people adopt a cat they will try and raise a cat for an 'inside' life. A friend has even trained her cat to walk on a leash, a great way to give him excercise.
Once again, I am not trying to be negative, and thanks for giving us the other side of the debate, I just hope a solution can be found so that neighbourhood pets can live in peace with each other and with neighbours.