Yeah, I'm aware of the legalities, but in most jurisdictions the law doesn't discriminate between airguns and firearms, so might as well use what's quietest. Although the authorities might still cut you a break for an airgun. That's a gamble.
If you can set up your shooting position a few feet back from a window or open door, it's much much quieter too.
I used to use my house as a 'silencer.' Crack the back patio door open and shoot from >5 feet back.
Rabbits in the far corner of the garden were about 35 yards away- a bit of a a lob for a CB cap, but just have to know the holdovers- used a soda can at varying distances to figure out where it would shoot.
Original tests were done with a lawnmower running outside to cover up any excess sound- ex would shoot, and I'b be outside to listen.
I was inside village limits, but there was nothing but corn fields and marsh for a mile behind my house, and all my shots were done at a downward angle towards a creek bed.
Oddly enough, I live out in the country now and and couldn't take shots like that because a housing development/subdivision 1/4 mile behind my house...