"Good Cat" is a very loose term to describe a feline with the ability to dispose of rats! Rats, as many will know, grow to a fair size, to quote many people , " I saw a rat & he was as big as me dog". Rats are well capable of killing cats when threatened so to qualify as a good cat it wouldnt want to be a big cat with a good mean streak I suppose! I woud like to stress I am not a cat "expert"!!!
With regard to how close you are to a rat at any time I have also heard its a lot closer than 100m also!