Cats will tend to not return to an area if they're severely frightened off... As we know though - all cats are different and nothing is a guaranteed...
I was interviewed for a job at Pets at Home, probably the largest network of pet stores in the UK. They said to us all that it would be great to hire...
As someone who has worked in kennels and rescue/re-homing in particular I can see why "no kill" policies don't work... But those numbers are insane....