My cats have always been indoor/outdoor as that is normal in the UK. They always wear collars with tags and are chipped for ID. I bought my house in rural France so that it would be a paradise for my cats after years of city and suburban life that was not always safe.
But 2 months after we moved and the cats were all used to going out here, I lost one to poison. I kept all the others in for almost a year, and then, after being told by everyone round about that they were sure that the person who put down the poison had moved away (they named that person), I began letting three cats out for 2-3 hours each day when I was in the garden, but not at weekends when the hunters are out. The three I let out are miserable if they can't have a run and also they are all hunters. My others have adapted to life inside and don't try to get out. But I am gradually enclosing my land so it will be safer for all of them eventually.
What I am trying to say is that there are no guarantees, wherever you are, but some cats do need to go out, especially if they have been used to it. You can only try to make their environment as safe as possible, and supervise them when you can.
But 2 months after we moved and the cats were all used to going out here, I lost one to poison. I kept all the others in for almost a year, and then, after being told by everyone round about that they were sure that the person who put down the poison had moved away (they named that person), I began letting three cats out for 2-3 hours each day when I was in the garden, but not at weekends when the hunters are out. The three I let out are miserable if they can't have a run and also they are all hunters. My others have adapted to life inside and don't try to get out. But I am gradually enclosing my land so it will be safer for all of them eventually.
What I am trying to say is that there are no guarantees, wherever you are, but some cats do need to go out, especially if they have been used to it. You can only try to make their environment as safe as possible, and supervise them when you can.