And all the people saying, “just secure your garden” ... I’ve already explained that this is not always possible with some cats and for some gardens.
Would you be happy for your neighbour to install a very high chicken wire domed fence on your boundary? Many people understandably would not want this as it makes the garden feel like a prison.
If your neighbour has any large trees next to their fence / wall, even high wire fences on top of walls, spikes on the too of fences and rollers may not work. You can’t always just take trees down, especially large ones.
Bushes as borders - forget it.
My friend who had a straightforward rectangular fenced garden had wooden rollers installed around the entire thing (not visible to the neighbours because the rollers are on their side). Well, it worked with one cat, but the other just took one look at it, jumped up and got over first time and was off on his merry way. Total waste of money.
What works for one cat, will not work for all.
Even the static cat wire boundary fences (which we use for our Ragdoll cat) does not always work with less timid cats or for cats determined to be on their way. We were warned it might not work before we bought it and had it installed.
Unless your neighbours literally build wire domes over their entire properties, there is no fail safe method to cat proof your house.
Also, don’t forget, if you have rollers or wire fence toppers leaning inwards to keep your cats in, if other animals such as foxes or other cats happen to jump down into your garden, they will also be trapped. Trapped cats in a garden which is another cat’s territory may hide and the owners will not know where they are. Foxes may become aggressive.
Please do share exactly how the people in the mystic land where all cats only stay in their own gardens have actually achieved this feat?