Going... Going... Going... 
(screengrab via SNY)

Okay, so this baseball fan absentmindedly did let his son careen down a steep hill in a wagon cart while he ran off to try to grab a foul ball at a Mets-Marlins pre-season game at Tradition Field down in Port St. Lucie. It's all caught on tape, so there's no denying that. However, in his defense, kids are relatively easy to come by. Lots of people have kids. And, you'll notice that his wife is holding a baby, so they've got a spare.

Sources: Major League Baseball | h/t Uproxx