Unless you own the lake there is not much you can really do! I agree 100% with your feelings on this 1, but you can't controll what others will do. If it were me I would just leave, fire up the big motor and make like a bakery truck. The route in which you choose to make your departure is up to you, also tell every body that will listen what happened and include a description. On the other hand they may not even known what they were doing! I was fishing a dock when another boat showed and meandered around til he got an invite, not a prob.