Astoria Modern Vet

So while walking my dog this morning, he appeared to hurt his paw. I tried to see what the problem was but there was nothing standing out. His paw was intact. Perhaps there was something I couldn't see. I decided to monitor it but made an appointment with the vet later on this afternoon just in case.

Low and behold, it's miraculously better. I cancel the appointment. Now, I was told when I make another appointment I have to prepay due to the cancellation. Literally 3hrs from when I made the call to when I cancelled it. I understand appointment slots come and go and it could've gone to someone else. It STILL can go to someone else, but am I wrong thinking this policy is ridiculous?