I constantly see people with obviously fake service dogs abusing the service dog system in the US and have for the last decade. I see them in bars, airports, and in the grocery store riding in the carts even!
I love my dogs and happily patronize dog-friendly bars with them, but the abuse is a moral plague and health hazard even.
Your dog doesn’t have to be a service dog to be in the airport. For your other examples it depends on if the establishment allows dogs or not.
I’ve specifically witnessed fake service dogs used for priority boarding but thanks for your rebuttal :)