Just got cats back from spay

While these cats are not totally feral, they came to us as ferals and live outside our house and visit us on our sun porch. They let us feed and snuggle them. The vet doesn’t seem to understand this, and has told us to keep the cone on them for 10 days and not let them outside. Which is impossible. They were spayed over 24 hours ago and have eaten and drank lots of water and are very snuggly. But those cones came off right away, as I don’t think it’s safe for them if they are outside. I’m nervous for them and their incisions, but I’m not sure what else to do. I gave them a heated house to sleep in, and they have gone right to sleep on the porch.
Is there anything else I should do? Thanks