If this is truly from DHS, then it is completely insane. For one, if it is for some important security function that presumably merits three exclamation points from DHS, then having it vulnerable to disablement by any casual passerby is ridiculous at best. At a minimum, the sign should carry some legal warning or threat of penalty.

Secondly, training people to think it normal that odd devices would randomly appear in public places (with no advanced notice or explanation and amateur signage) is a horrible idea. Coming from DHS, it's even worse.