[tet68]

Coast Guard officials say they are authorized by maritime law to board and search vessels on U.S. waters, including waters that lead to U.S. waters, to enforce federal laws.

Including navigatible waters, this means the Mississippi,
the Tennessee, and other large rivers, if you cruise on
them THEY have jurisdiction and THEY are the law.
You must be prepared for a safety inspection, this is not
your average lake.

Still sounds odd though, more like a drug tip, etc.

[Jack Black]

Coast Guard officials say they are authorized by maritime law to board and search vessels on U.S. waters, including waters that lead to U.S. waters, to enforce federal laws.

Big Freaking Deal. The FBI is authorized be federal to search houses to enforce federal laws, the state police are authorized to search buildings in the state to enforce state laws, the local po-po are authorized by state and local laws to search local houses and buildings for violations of local laws but in all cases THEY NEED A WARRRANT. Saying "maritime law" is not a magic incantation that makes the Constitution go away. Maritime law is bound by the limits of the Constiution just like every other law promulgated by a US political sub-division. The real law they have backing them up is "Might Makes Right", there are six of us w assault rifles, and one of you in your PJs in the middle of no where. Time for another Vin Suprynowicz book.

[PistolPaknMama]

You must be prepared for a safety inspection, this is not your average lake.

At gunpoint in the middle of the night?

[Mathews]

Yep, there had to be some sort of intell here. I don't see Coasties just showing up, at night, to conduct safety inspections. They were looking for something/someone else. As far as the owners go... well, if it were me conducting the searches/inspections, I'd say, "The job comes first." I wouldn't worry one bit if someone got their panties in a bunch. Let the lawyers hash it out.