because i play by myself i end up playing thru groups quite a bit... i usually try to establish some kind of contact before i ask to play through... eye contact when i walk up to the tee, smile, friendly wave if the group in front of me notices me waiting on the tee... that way we are all warmed up to have some kind of interaction... sometimes it works, sometimes it doesn't... my fave was a few months ago at horning's when a group of 7 wouldn't let me play through... because there was another group in front of them. i totally bitched out at them (oops) and was like, "is it because i'm a girl??" and then also mentioned they were teaching really excellent etiquette to the young boy they had in their group... i skipped ahead a hole... almost aced it, then the group in front of them let me play through and i proceeded to birdie most of the other holes, i circled back to the hole i had skipped, just being finished by the big group, and was like, "yeah... that really would have slowed you down to let me play through, huh?" and then parked that one, too. they didn't appreciate me one little bit... but i hope it helped them to learn in the long run that it's okay to let people play through. i admit, tho, not my finest moment, but at the same time pretty satisfying.
i really do think it's rude to play in a group more than 6... and only 6 if it's pretty competent players who are going to move along at a good clip. you've really got to consider the other people who are using the course, too... if you are gonna play in a herd... pay attention and take the responsibility to be aware and step aside for the smaller groups.
on another note, someone mentioned when people want to join up... this happens to me, also... and i've come up with the statement, "naw, not today. today i'm working." it's legit and doesn't make people feel bad that i don't want to play with them... because, i know, i am so very cool that everyone wants to play with me, right?