British tourists detained, deported for tweets

In a scenario that vaguely recalls the film "Like Crazy", two British tourists are being detained and deported for a "threatening tweet", as in this Huffington Post story by Allie Compton, link.  They also went on a watch list quickly.

Homeland Security is putting people from modern western countries like Britain on lists because it is difficult to parse them from hostile immigrants, as from Pakistan and other places, as in this World News (website url) story. It takes loosely worded statements on social media quite seriously.