a) I didn't know as I was 22 and this was my first time getting a job after everything happened, so I was ignorant of the process. The subject never came up during interviews or offer signing.
b) NYC has laws/rules (?) that don't let employers ask about criminal records before giving an offer. To me these laws are useless as I'd rather be rejected up front than accept an offer and then have to leave...
Anyway, the company was a CRM start up and their excuse was that their investors wanted everyone in the company to be clean because we handle customer data or whatever, so I doubt I would've gotten the job even if I had been up front. But, I love where I work now so it's all good.