I talked to my wife about this and she said the sign on the facade was actually on the house panel. Her "open" sign and the other plug ins were on with the front of the store overheads. The "show window" circuit also fed the two wall receptacles in the front of the store but they were sort of close to the window.
Can the 20a sign circuit serve multiple tenants?
That would seem to be the case here. The landlord owned the sign can and the tenant bought the lens with their name/logo or whatever on it.
