i recently saw someone bringing a guide dog onto a flight. the dog was all decked out as a guide dog, but i don't think it was. was a border collie, with the owner, and was standing on two back paws against the check in desk, getting head rubs from the gate attendant.

while i watched for the next 5 min. dog did much more following than leading. i was unable to notice any defects in the dog's master.