1. players can't be kicked
2. if they run you down in a RIB then either the session master set it up as a rib vs sailboats race.. OR
3. the RIB drivers did not understand the RIB is for umpires/spectators only
4. RIB players really very badly needs a dose of points for his ranking fix

If you set up a session and it is open the only chance you have is to make is for 1 single boats class only
but that will not get rid of the "pirates" either.
Put up an organized session with a password and you can decide whom you give the password...
OR put up a private server and let only those in you give acess ... (google for ad-hoc virtual private network ) or check out
https://secure.logmein.com/products/hamachi/ OR put up a public server and let anyone in that knows the server address
"As far as I can remember, there aren't a lot of points of land or holidays named after people who sat at home and criticized Christopher Columbus."
(Paul Cayard, from the Pirates base, in an e-mail to race HQ. 25 Jan 2006 volvooceanrace.org)