hey man, he''s on topic, and relevent, and it''s not machine posting. I hate spammers more than anyone else in the world, but i dont see the problem with this.
back on topic...
Crewing is as safe as going on a road trip with the other people on the boat. You dont stand by the docks with your thumb out, you meet people, talk to them, look over the craft, discuss plans, and then go sailing.
So meet them, and talk to them.
Do they seem to be at your level of sanity? are you comfortable with them, and their attitudes etc?
Go to the boat, look it over. Is it safe for the type of cruising you''ll be doing?
then go on a day sail with them, and see how things work on the water.
from there, the only thing left to do, if you havent run screaming from the psycho, is to go sail with em