Because, he just might run around in and out and all around every bra/panty display in the whole section and then spot a certain larger size bra in a leopard print, pull it off the rack and declare:
"I'm a cheetah, I'm a cheetah"
While still running around of course.
You may not be able to contain your own laughter, while trying to maintain order and demand that your son put that away 'right now'.
And wondering how many people just saw him do that and are staring at you as you shamefully return to your bra shopping.
While steering clear of a certain leopard print item.