I wouldn't poof the cat just because he flinches. My boyfriend's female kitty, Mau Mau flinches at sudden movements and loud noises. She will either roll into a ball or croch down like she is awaiting a blow. She is NOT ABUSED! If anything, we spoil her rotten. She also gives constant head bumpies and loves and is a complete love bug who climbs in your lap at every opportunity. I would not want someone to poof her if she got outside just because she flinches. Some cats are very sensitive to movement and noise, but they are not being abused. Now, the being outside on several occasions does worry me a bit. Give the kitty back and tell them you are worried because he is outside a lot and you are sure they would be heartbroken if he disappeared. If you keep finding him outside, then maybe he should be poofed. But I would talk to the owner first.