One person. A lot easier to slip past than the boat, certainly.

He stops, thinking for a moment, before coming to a decision. He slips off his helmet and mask, zips up his jacket, and messes up his hair. If he's caught, he can play it off, a joyriding teenager looking for a ride, or a cash-strapped junkie looking for an easy score. Nothing traceable to the Red Hood.

Then, slipping a tracer into his hand, he drops quietly to the ground on behind a building opposite the chauffeur. If he can pull this off, he can stick the tracer firmly to the underside of the car and slip back behind the building while the chauffeur is still busy reading the newspaper.