I wouldn't say it's movie overkill. While most police and sheriffs wear uniforms (except detectives), most federal agents (of which I was one) do not. If we were doing a raid, even at a single family residence, it was necessary to have at least two teams, front and back, and often there were officers from more than one agency, plus local police; and in low-light conditions in fast-moving situations, identifying the good guys from all others was crucial--you just can't be too conspicuous. Also you don't want to have the bad guys shooting you by mistake thinking it's a home invasion by rival drug robbers. If they do shoot you, you want to be sure they can't claim self defense on that basis.

I had not only an armored vest with embroidered badge and MARSHAL on both sides, but also an inconspicuous jacket that had pull-down flaps with the ID, which could be pulled down, plus a light nylon jacket with neon yellow paint on both sides and down the arms that practically glowed in the dark for non-threatening situations.