During street demonstrations against the trade talks being held last year, police were pretty heavy-handed and (some say) brutal in their crowd-control tactics. Supposedly this was necessary because of the inevitable radicals and trouble-makers who showed up (and yes, they were there!). But the organizations that went to court and succeeded in getting settlements and apologies from the police were not anarchists and vandals, but were venerable and benign traditional protestors like church groups and elderly citizens' and labor organizations. These people had gotten the permits, followed police instructions, and otherwise exercised their rights peacefully.

To be honest about it, I don't think this is so much political as it is economic. Miami is very keen on playing a role in South American trade, there's big bucks there for everybody, and I suspect the word came from the city fathers to keep a lid on things.