Rusty...
Not sure what your backround is, but rest assured the Coast Guard "Rules" carry the full weight of law behind them.... You can and will be cited by the USCG for breaking any of them! Violation of any of these "rules" in the wrong circumstances can and will result in death or serious injury! Most of our existing boating RSA's take thier language DIRECTLY from USCG Rules & Regulations and the COLREGS!
International Maritime Law has been around alot longer than this country has existed! Most of the laws we have on the book in NH and the rest of the US regarding safe boating operation come directly from COLREGS!
http://www.boatingsafety.com/colregs.htm
If you notice, the COLREGS (also adopted by USCG) are broken off into numbered sections.... Rules 1-3 define the terms used. Rule 4 on defines the actual Rule of Law.
Also... last I checked there are no "signs" bobbing in the waters of Lake Winnipesaukee telling you what speeds are allowed. In fact I dont recall any signage at the boat launch either!
Woodsy