The frosting on the red velvet cupcake was a little too much like a gel, and thus violated the TSA ban on liquids and gels. The TSA performed an analysis on the cupcake and determined it was delicious.
OK, I made the last bit up.
And they ate the last bit up.
I think The Onion needs to sue real life for stealing all the good stories.
Video of the perpetrators:
Epic Cupcake Time - YouTube 
(Parody of My Little Pony and Epic Meal Time! so there is NSFW language)