[HereInTheHeartland]

“What right do people have to think they can plug their personal device into any open plug?”

That’s like asking why were passengers using the air conditioning.

[11th Commandment]

Wrong, air conditioning is provided for the comfort of the paying customers. If I am waiting for the Doctor, he/she is providing a comfortable environment for me or I am walking out the door. He may even provide WIFI on an open network which implies public use. However, open electrical sockets do not imply public use and should only be used with permission of the owner. In this case, signs were clearly posted that the electricity was NOT for public use.