I'd like to add my personal favorite experience...

In San Francisco, first Saturday of every month, there's a shanty sing down at the Maritime Museum on Fisherman's Wharf. The few times I've been in the area and managed to make it, it's been heaven...
The only rules seem to be:

• Songs must be in some way sea-oriented
• Don't hog the floor
• Bawdy songs must wait until after the 11 p.m. bell
• Have fun

The times I've been there, I've seen professional bands that show up with full instrumentation, play one or two numbers on their own, and back up the rest. I've seen adolescents with their painfully cracking voices sing songs in new ways... some of them good. I've also heard some of the most obscure shanties I've ever imagined (5th century BC Hebrew fishing song among others), and gone away enriched from the experience. At no time has anyone ever been asked or criticized for their experience or lack thereof... everyone is made to feel welcome.

My two cents...

M