Andy 7- you sound pretty courteous and with common sense and I don't want a disagreement either but I don't see much evidence of either virtue in the various scurrilous tales in this thread in the interim!
So it may be that 'notes for the aspiring folkie' ARE necessary?
   Your observing before rushing in is apparently your way of approaching new experiences & laudable in many ways...
   BUT- I don't accept you need to worry about what to do/say AT ALL-, there are strong and intolerant knowalls on the scene who KNOW what's correct and you really do not need to be guided by this.

Singing a Fenian song in Portadown is obviously a bad idea (for the sake of your health) but if people sneer at you singing 'Kumbaya' or the 'Wild Rover' and if Cyril Tawney can finish a folk club night with 'She wears Red Feathers' then so can you- I bet they didn't sneer at him!
Seems you've been around a while now, as have I - maybe you're just a bit less cynical than me!