Early this year I shot 2 squirrels from the top of a Picea Mariana (for those that are bemused) its a tree ! both safe shots and both squirrel,s passed away after being hit with a 55 grain Nosler Ballistic tip from my Sako75 3 22.250 from 225 yards away.
The thing is
I made the decision that the shot was safe, a 20 acre field that I could see was void of anything living other than rabbits and worms was a good enough backstop. The shot was taken looking downwards to that field.
IF any rifleman can't risk assess each shot is taken, then I'm afraid in my book they should go back to water pistol. But you could always ask the PW H&S board prior to each shot, with of course a full 3d photo plus rang,angles ect.
Oh! And of course a copy of your FAC stating rifle being used.