To be fair, I can understand why the neighbour is annoyed - I mean if people let their dogs roam loose and mess everywhere then all hell would break out, but for cats its ok??
I adore my 2 boys and love cats generally, but it still annoys me to find other cat poop in my garden.
My boys aren't free roaming yet, they go out in the garden when we are home, but they have never poohed in the garden, they rush in, use the tray, and go back out to play again.
I will also be putting a tray outside when they go out full time for them to use - I wouldn't want them poohing in my garden or anyone elses. I know I can't stop them, but I can at least try.