Why was security telling people they couldn't have Q apparel at the Trump rally?

Saw it on RSBN before the rally started. Caught the security guard live telling folks in the crowd they had to take it off or turn it inside out. Who hired these guys?

Noticed the Youtube feed of RSBN is 5-7 seconds behind the Rumble feed.

I'd rather give my view to Rumble, but found that interesting.