A reader sent us the above photo today, saying "a friend snapped this on the new E train this morning, and no one can figure out what it means. do you guys know?" We asked the MTA and they told us: "A quick check says this is not an icon we use. Looks like the sign was vandalized. And I won’t even hazard a guess as to what it is meant to represent." So what do you guys think this vandal is trying to get fellow straphangers to stop doing?