Fake service dogs

[Shakou]

I've come across this a LOT in my travels, primarily with homeless dog owners, and traveling vagrants. They basically print out some fake service dogs tags with a picture of their dog, their name, their condition, etc. and use it so their dogs have full access to everything a regular service dog has. The owner can bring the dog on buses, trains, in stores, etc. and no one, even if they have reason to suspect the dog isn't an actual service dog, can question it.

I don't know why, since in MOST cases, it's not hurting anyone, but this REALLY annoys me. Anyone else ever run into this? Thoughts?