IDW's Editor in Chief Chris Ryall posted to his Facebook page that he has learned that a prison in Arizona blocked inmates from receiving the Previews catalog with the cover of Back to the Future.because of nudity.
I couldn't imagine that IDW would put nudity on a cover of Back to the Future, and even if they did it would've been censored in the Previews catalog. So I asked Ryall about it. I was told that getting messages about certain books being blocked because of overly suggestive outfits or contents is common. But this was the first time he'd received a note about the Previews catalog.
Most likely it was something else in the catalog, but it is funny to think that Back to the Future was the cause.
Here is the covers for Back to the Future #11 and Back to the Future: Citizen Brown #4 from the most recent Previews catalog.