Upon further review:
In this link:
http://www.faa.gov/safety/programs_i...dia/PART04.doc
Starting in section 4.3.1.5, gives the marking locations.
Under the left wing
On the vertical tail section (both sides)
On the fuselage (both sides)
(the engine pod stuff doesn't apply here)
In looking at this airplane, it almost looks like it may have been recently stripped of paint and repainted, or at least in the process of repainting.
Certainly, we should be able to see one area that requires the "N" number to be displayed (N= US registry.)
Looks like a job for Homeland Security

. Maybe we'll see this episode on TV on Tuesday nights!!!!!
Off topic, but as an aside, I had forgot how many Government documents had "this page intentionally left blank" . As I remember it, it didn't matter if the document was printed on both sides of a sheet or just one side. I guess they are leaving room for further expansion

.
Back on topic...As far as over open water, until the civilian and government lawyers get involved to further define this question, I personally think that open water that is frozen would still be considered open water. Buzzing boats on that water is still a no-no, so buzzing snowmobiles would likewise be a no-no. And I don't think that group of bobhouses constitutes a village or town

. (sometimes it looks like it)