As a "themer", I would have a particular problem with this, belonging as I do to a subculture that involves frequenting lame theme nights in pubs and nightclubs. We get dressed up according to the theme, and then wallow in the irony of enjoying ourselves while sneering at the pitifulness of it all.
If any venue were to run a Themer Theme Night, we might get caught in an ironic recursive loop which would almost certainly result in our utter vanishment up our own fundament. It is too horrific to contemplate.