Yes, I fully understand, it's very different in big places....
When/if our huge Labradors/Boxers etc had to go to 'big' daycare, then I didn't tip. But in their Reception office there was a 'Dogs Trust' (one of our major re-homing charities) container for donations, and I would always pop something in there....just because I felt so fortunate that we were in the position to be able to provide proper care for our dogs....
Sally + Harry x