Although risk of collision with a drone is meaningless and any ship would be stupid to alter course because of a drone (unless there is a specific terrorist threat regarding drones), it can be a major distraction especially during a mooring evolution (and especially if the drone is right in front) which requires a lot of concentration. The last thing we need is for a ferry to run aground or have a allision with the pier because the crew lost focus because of a drone buzzing about between them and the pier. There is also a standoff distance post-9/11 (and post-Cole) for security reasons. We here should know that consumer drones can't really see effectively inside a ferry pilothouse, but there is a security element to consider which is based on potential explosives delivery, however small the charge is that can be carried by a small drone. There are usually passengers milling about at the bow and stern on the ferries exposed so it wouldn't take much. Also, the basis for restricting access to the pilothouse is more akin to restricting access to a plane's cockpit in flight and is based on physically letting (or rather not letting) people into the control space while the vehicle is operating and is also a post-9/11 thing and has nothing to do with seeing into the pilothouse.
