Hi Snail - perhaps you are right - but e.g. Hardraw seems ( after reading reviews) to have a good sesh - but I unfortunately elected to go to Durham which is obviously not Yorks. but I know what you mean.
"Tunearounds" sounds good to me, it sounds like that it might cater for all levels which a session DOES need so that we can all improve though I also could do without the "speed merchants".
Put simply I play when I know the tune , or go to the bar / stretch your legs / go quietly through the motions when you don't, but above all enjoy it,have a laugh and try to iron out the mistakes in time for the next sesh, whenever that maybe. Sometimes there's a few too many serious faces amongst the musicians.
Mr Happy - good observation re groups doing the leading - for me better to have an individual to start it, let it run , and kick some energy into it if it starts to run out of steam / ideas. No need to dominate the choice of every tune and good individuals like those I mentioned do the job right.Have fun.