I had the same problem. Jezebel's vet insisted she stay overnight. It worried me so much I stayed up all night getting YT advice. I called the vet the next day and told them I was not going to let her stay over night because there was no one there after 6 pm. The receptionist informed me they could not do the procedure unless she stayed there afterwards.
I had all of her vet records transferred to a different vet office. On April 10th, she was spayed, microchipped, and had five teeth pulled. She came home late that afternoon.
I will never regret the discission to change vets. Her new doctor is much more caring and I trust him more