It was fun while it lasted. The "etiquette" posters which a New York artist has put up in the Subway system are apparently themselves an example of bad behavior.

I blogged Wednesday about artist Jason Shelowitz's "guerilla art", posters he created based on Subway pet peeves. The posters encourage Subway riders to keep their hands to themselves, their music to themselves, their religious views to themselves. My favorite poster warns against clipping fingernails on the Subway. "It's crazy that this even needs to be mentioned," the poster states.

It was a crazy, funny idea. Subway authorities, however, are not amused. Putting up posters without permission in the Subway carries a $25 fine. "These posters were not authorized and will be taken down," the MTA's Deirdre Parker tells CNBC.

They're apparently coming down Thursday night. Shelowitz was not aware of this when I contacted him.

"I have seen MTA workers read them and laugh without taking them down," he said. "A friend saw MTA workers putting up actual service change posters around one of mine and they left it up. This may be a generalization, but it seems that the MTA likes the posters."

Not everyone likes them at headquarters. But good luck finding the posters. Shelowitz says he only put up a hundred of them, and regular riders have taken many of them down as mementos. "This whole thing is spreading wildly over the internet," the artist says, "but there are so few physical posters out there. It's almost comical. It just goes to show you that you don't need to make thousands of these things to get your point across."

Maybe the MTA should focus on people clipping their nails on the Subway rather than go after some guy who's trying to remind riders to be civil. Just sayin'.

But Shelowitz is ...politely ... refusing to back down. "There are another 200 or so (posters) to put up, and I will continue to do so until I am asked to stop."

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