Washington (CNN)Beware presidential candidates: Pranksters are on the loose.
Wisconsin Gov. Scott Walker and billionaire Donald Trump encountered one of the age-old risks of the campaign trail on Monday as activists and others deployed gags against the candidates.
A Guardian reporter tweeted this photo of Walker on Monday, during a stop in New Hampshire.
"Scott Walker agreed to take a pic w/this guy whose sign said "Walker 4 president," but then he flipped it around... " tweeted Sabrina Siddiqui.
The two activists, from the environmental group 350 Action, flocked to Walker seeking a photo -- like so many other activists do. However, just as the shot was being taken, they flipped over the sign they were holding to reveal a fake check for $900 million, "payable" to Walker.
As of Thursday afternoon, the tweet was retweeted at least 1,900 times and favorited at least 1,700 times.
Meanwhile, Donald Trump was roped into what he thought was an endorsement by Harvard University's student newspaper, The Crimson.
It was not. Instead it was legendary pranksters, the Harvard Lampoon, who drew Trump in.
The actual Crimson recounted the somewhat more elaborate prank -- which involved stealing a high-back wooden chair -- in a report Monday.