That's not my experience. When I brought in my model 3 to Oakville they said that they'd give me either a loaner or rental on the day I got there. They tried to find a Tesla loaner but didn't have anything so I had to take a BMW from Enterprise. They didn't seem to look down on me, it's just the fact that they didn't have any loaners at the time.
Somebody on this forum said that if you were willing to wait, you could make an appointment for when they have a Tesla, but it's a long waiting list. I really just wanted to get everything finished so took the first service slot they had open.