Our ddog has been in the vets for a couple of consultations and some tests.
We arrived in the car park and they came out and got him, took him inside for the consultation/tests then came out to talk to me after. They have a gazebo (roof only) if it is raining to talk in.
He had to go to the vet hospital for an MRI, we talked on the phone about what would happen, then dropped him at the door in morning, when when we picked him up at night they let dh and I in with masks to discuss but they had much much bigger rooms with open windows, in our vets the rooms are tiny and mostly windowless so I can understand why they can't have people in. Afterwards we waited outside for them to bring him out to the car.
when we are picking up his meds, we arrive in the carpark, call to say we are there, the receptionists will bring meds out and put in box attached to the railings and we will go and collect from the box.
works ok for us, but if there was a PTS situation I would hope they would make suitable arrangements. my nieces cousin is a vet and says at their practice they have a covered area outside the back of the vets, which they have tried to make as nice as possible, where they can PTS with owners present.