The only reason I saw anything about it was a few weeks back, when it was so rainy it was going around the Indy Car and NASCAR garages. There was a pictures of Jimmy Johnson planking between his and Dale Jr's car and some of the Indy drivers were doing it on stacks of tires during rain delays of practice for the 500.

Not something I think I'd really get into, but unless you are stupid about it, seems pretty harmelss.