dumb waiters

[redsauced]

In a related topic, what do you guys think about offering the waiter, or sommelier a taste. The few that appreciate what you bring seem to enjoy the chance, and I find that sometimes the corkage fee goes away. Is there an offical custom here? I've heard it's at least polite to offer. And is it bad form to bring a wine that is on the list? You can't always check a website beforehand.

Thanks for the insight.

dave