Great idea! I just blocked them too. They've been calling me non-stop for the last month. Wish I thought of it sooner! They just called me at 8:50pm, which is way to late. If they woke my 1 yr old (who had major trouble falling asleep), I would have been livid.
Its so annoying to HAVE to put your phone number down in order to buy tickets to anything "in case we need to contact you". But they always use it for some marketing crap instead of a problem with your credit card or ticketing. I went to the symphony recently but find going into the City, parking, and driving home are a major pain. Not enough to make me want to go again. Don't even get me started on the creeps, barf, and crap on BART. I gave up on riding BART late at night, a long time ago. I hate those after market calls where they call again and again until you answer the phone. It only makes me crabby and less inclined to go again. Blocked.