What, the idiot protesters can't film from 20 metres away?
Personally, I think a buffer of 100 metres would make more sense.
A mile might be a little excessive.
Funniest thing I ever saw on TV, many years ago, was protesters at dockside in Newfoundland. One took it upon himself to charge up the gangplank onto the foredeck of a sealing vessel..........two beefy Newf crewmen obviously thought he needed a hand, caught him by both arms at the top of the gangplank, helped him across the foredeck and over the rail into St. John's harbour.