I think I have seen such South American bands in France doing those kinds of things, they sound great.

I don't want to knock people in sessions mostly all playing the tune. That's quite difficult and I only wish I could do it. But, I have this suspician that a bit more variety in terms of pitch and bits of tunes and a bit slower might sound ok. Brass bands etc. do it all the time.

The question is do you need to be a sight reader or do you need to be an ace improviser in order to contibute?