The logo was created by Bethesda. It doesn't matter if the nightclub's use of the logo isn't taking money away from Beth, but it does matter if use of the logo might be earning money for the nightclub with no kickback to Beth. In which case a lawsuit is no stretch of the imagination at all. As for dikes, we are talking about a company which took another company to court for calling their game "Scrolls"...
Bethesda Softworks never sued anybody for calling a game Scrolls.
How? They just stole a logo. 98% of people at that place won't even know. The few who do, may think "OMFG I PLAYED TES THIS MUST BE A TES HANGOUT!" and that place gets money it would never have gotten.