Re: dear god, the spambots...
Personally I use passworded games. Seems to sort out the majority of problems with bots.
Try leaving the text on screen until the bots leave whilst being surrounded by a group of gloams, minotuars et all!Honestly the "N" does very little to help. When you have 4-5 spam bots that join all spamming ~20 lines each you're basically pressing N until they all leave. Might as well just let the spam sit on your screen it's more or less the same thing.
Level restricting games is certainly your best option, but I have seen lvl 90+ bots although they are much less common than the lvl 1's.
Personally I use passworded games. Seems to sort out the majority of problems with bots.