As much as you may not like it the lake itself is a public area. Weather having an anchored boater or fisherman casting under your docks etc. it's public and owned by the State of NH. I do find it lets say stressing when they are close to the front of your property, but it is actually more that they are inconsiderate to be so close in many cases. If you find they are over nighting then call and kick there .......... out.
When it comes to the let's call them unsafe boaters, you still need to keep your cool
to insure the safety of your vessel and passengers. Unfortunately there are not going away and will probably only get worst. I have found myself not going out on warrior weekends any more between the unsafe boaters, parking battles at docks, speed limits, kayaks etc in the middle of the Broads, and motoring sailboats thinking they fall under sailboat rules (your a motorboat at this point). Commons sense goes along aways please use it.