The people caught on video stealing the glitter bomb were in on the "experiment" - what was shown in the video was mostly or entirely staged. (find the apology from Mark Rober on YT :)
Huh... hadn't hear of that... from what I understand after a quick search: 2 of the reactions/shots were not genuine thefts, but this was not exactly intentionally faked by Mark Rober, but by the people who he enlisted to help bait the porch pirates. Mark offered a reward if the people he enlisted as porch baiters were able to return the stolen boxes, and they took it upon themselves to make sure the "thieves" would "return" the packages somehow.
That's not my memory of the situation, and a quick Google confirms: only a few of the thefts were fake, and Mark Rober didn't know they were fake. The intention was for all the thefts to be legit, it's just that he paid some friends to help him get the package stolen (by putting it in front of their houses), and those friends apparently cheated him.
Unfortunately after those one or two fake sections were caught everyone assumed everything was fake, and the internet took up that gossip like wild fire, tainting the whole video. Bit of a shame, and apparently that lie persists.