I'd say we're generally a very friendly bunch, but as with meeting new people sometimes it takes a few meets to get to know faces/names and its a bit unfamiliar until then.
When i first went to a scooby meet about 6 years ago, i found it difficult to start conversations etc as i was the newbie (this was in the sussexscoobies days). I ended up talking to Clive and Stiggy i think, and it was their first meet down at the Flight Tavern too.
I wouldn't say its cliquey, its just natural that the regulars we all know and get along with find it easier to chat together. We always try and welcome the new folks though
Only way to find out is come along to a meet and see what you think, its normally just standing around in a car park for a while nattering and then getting some food in the pub