Last Monday, two British tourists were denied entry into Los Angeles after one of them said on Twitter that he was going to "dig up Marilyn Monroe" and "destroy America" in two separate tweets. (The latter tweet was apparently British slang for partying.)

The pair, Leigh Van Bryan and his friend Emily Bunting, told the Daily Mail that agents from the Department of Homeland Security searched their luggage for spades and shovels, on the assumption that Bryan was serious about digging up the body of our famed, white-clad starlet. Customs then held them in a detention facility overnight before sending them back to the U.K.

Given the propensity for revolutions and social unrest to develop on social media, it should come as absolutely no surprise to anyone that the Federal government is monitoring Twitter. It has even gone so far as to seek help from tech developers to build a social media monitoring application.

After the incident became public, the Department of Homeland Security issued a statement to the New York Times which read in part:

CBP denies entry to thousands of individuals each year on grounds of inadmissibility, some of which include: improper travel documents, prohibited activities or intent, [...] posing as an imposter, and national security concerns, among others.

Apparently, "national security concerns" can include a general, joking tweet. DHS agents are also apparently too technologically illiterate to realize that a) people make jokes, and b) anyone who was really, actually planning to "destroy America" would likely not be dumb enough to use those exact words in a public internet forum.

So remember, next time you're at the airport, maybe don't make that joke about wanting to kill everyone in front of you on the security line. It might actually land you in jail.