I suspect it is illegal. It looks like a high-capacity vest with more than five pockets, and several of those pockets are capable of holding more than ten flash drives.
I lived in Arlington for 3.5 years. The cops in Arlington...are five-star law enthusiasts. They can take any law....state or county...and whip it into a $500 fine very easily. But when you compare them against the DC cops....they are five times better and more competent.
Last year, they had one of their cops take a break at a local mall...and his cruiser-car was stolen. No kidding....the guy got into it, crossed the wires and drove off across the river to dump it in some local neighborhood.