In a number of videos (example), recently in Florida there was an on-going theft of a jet-ski. The police approached a boat owner who had just launched his boat for the day and asked if he would be willing to take them down to locate the jet-ski.
The owner, instead, offered to allow the officers to take the boat themselves (without him on board), and they found and arrested the thief. This was a sort of voluntary commandeering of a civilian vessel during an active pursuit.
What risks would there be to the owner, if the event had turned out violent (perhaps the thief shot and holed the boat)?
If the officer piloting the boat did not have a captain's license or any other boating certification and proceeded to cause damage to other's property?