If you cannot keep your birds from wandering off your property, you need to pen them securely. Otherwise you're just as bad as the people who let their dogs and cats wanderMy neighbors let their cats roam around in other peoples property..
Also, I have tried so hard to keep my turkeys in but they just want to get out. They do come back home to roost though.
Of all my birds, only my mallards stay in my property. So it is not that I just "let" them wander, but they choose to wander and I can't really do anything about it. I need to keep them flighted so that they can get away from the foxes.
Those guinea keets were somewhat of an impulse buy
But if anything goes wrong I can just give them to my cousin (his neighbors do not care about noise).