The US Military will be playing their war games in Hillsborough bay between The convention and the MacDill airforce base south of the convention.
Homeland security is assigned to protect Federal property from vandals, like the Federal courthouse, US Post Office , Social Security, etc, so just steer avoid passing through those areas.
Ambulances need access to Tampa General Hospital, and ONLY the roads in Down Town Tampa lead to the hospital, so yes, barb-wire. A road may be closed to vehicles, but might still be accessed on foot.
The Sheriffs will be patrolling the waterways within their jurisdictions. Tampa Bay straddles three different counties.
Tampa Police will be within the city's limits.
The US Coast Guard will have their hands full with drownings, rip tides and stranded & lost boaters.
The police only want things to go smoothly & everyone to be safe. They KNOW the whole country is watching via video cameras and Tourism is our bread & butter, so they don't want a bad image.
Don't freak out, speak to the police like a respectful human being and they should respond like a respectful human being. Smile! Be respectful. Do what Doctor Paul would do in the same situation.
There IS a strategy to the barb wire. Occupy has openly announced they do not plan to follow 'the rules' so how do you expect security to respond?
It would be wise to study a Convention map of downtown Tampa so you don't get caught in traffic jams or innocently swept up with Occupiers.