THIS ^

If one person gets bit the owner is where the lawsuit is going, legit service dog or a fake one wearing a sweater.
I do not know if each state has it's own verification paperwork or it's national, but I'm sure it's as abused as handicap parking permits are.

That being said, I was like "WTF is a dog gonna do if it's owner has a heart attack, give CPR?", and a quick google search gave the pretty amazing answer...

"Cardiac alert dogs are service dogs that have the innate ability to warn of impending drops in blood pressure (typically seen in individuals with cardiac syncope conditions) which often cause loss of consciousness. Advance warning allows the individual to take essential medication, lie down, rest, and elevate their legs if needed."

So if your friend is an attorney I would expect him to follow up with law enforcement, as I'm guessing the is a fine to be paid by the arcade, or a real big apology.