My car story is a little different... post-first-hip, we had three youngish cats, all of whom loved laps but only one of whom was allowed to sleep with us, which she did either between us or on hubby's legs-- never mine.
We got me home from the hospital, and I sat me down on the couch while exhausted and needing my pain med. one of the cats meow-ndered in, to say hello. Before I could stop him, up on my brand new anterior incision he leapt, all 12 lbs of him. I shrieked, he set his claws and launched off my lap, landed running, and didn't come back in that room for hours. From that moment on I put a flat chair cushion on my lap every time I sat or lay down!
I did have one concern about that little episode, and that was the bloody claw marks on my thigh (summer clothes, no protection), very close to the incision. Cat claws are so very not clean! So I'm thinking maybe the surgeon doesn't want any chance of a bite? OTOH, maybe he just doesn't like animals and is ignorant of the overwhelming therapeutic effect pets have.