Shorts appear to be Flow Society lacrosse argyle patterned men's shorts. The circle logo on the bottom of his right leg seems to confirm that. (https://www.google.com/search?q=flow+society+argyle+shorts&rlz=1CDGOYI_enUS590US590&hl=en-US&prmd=sivn&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjb08-ewKHMAhUM1R4KHbf3CIIQ_AUICCgC&biw=375&bih=591) Haven't done much digging on the tank's logo ("say no to pox"?) or other identifiers. Maybe tomorrow.
My guess is that someone scanned a real bib and went to work on Photoshop as to not get the legitimate bib owner in trouble. The font is much slimmer on the two duplicates than on Greta's original. Additionally, it looks like she's in corral 7 (or whatever the smaller number below means), whereas the two duplicates are 5s.
It's possible this guy or girl produced 2 of the #14707 and likely a few other number combos and sold them on Craigslist or something similar. He or she probably claimed it was a legitimate bib but injury was keeping the seller from running.
The two bandits don't appear to be near each other or even similar in age, which one might expect if they'd been in on this together. If it had been two fratty guys, fine, but that doesn't seem to be the case. Also if you know you're wearing a fake bib (or a stranger's duplicate), it's easy to avoid getting caught in photos by pinning it to your back or side. My guess is they didn't know theirs weren't authentic. I could be totally wrong, though.