The Bush's actually fly into Sanford, not Pease. They take motocade to K-port.
I live not far from Walker's point. When the family is there, it's not that big a deal it's when he's on the move and streets get closed, etc it can be a pain.
When Bush's boat is on the mooring ball, two divers inspect it before they bring him out to hop onboard. The have a Coast Guard boat that patrols around the property and if you try to get close on the water they will send you away from the area. There are cameras all over the property. I ride my bike along Ocean Ave and the property is fenced and you can see they have every angle covered.
If Romney becomes the GOP candidate and/or the president, I suspect a fairly large area will be blocked off as a restricted area on the water. That would likely be the only impact on the water.
When the motorcade is on the move, the streets are closed, they have a couple forward posted vehicles that conduct sweeps and then next thing you know the limo streaks by with agents hanging out of vans and suburbans in close proximity to the president. The motorcade does not follow the posted speed limit that is for sure
