That is exactly how it is handled, even if it's a regular, local CG
patrol craft that boards a recreational vessel and finds illegal drugs
or weapons. The local police department is called who meets the
offending vessel crew at the dock and arrests them.
The Massachusetts Environmental Police are the ones everyone watches out
for up here. They have broad law enforcement authority, more so than
even local or state police departments. They also operate as part of
Homeland Security assets. A MEP officer can even stop you for a traffic
violation when driving your car down the highway.