Just withdrew my candidacy from a position because they were adamant about current salary disclosure.

I'd talked to the company's recruiter and he'd said that they do need that information but I didn't think they'd be this adamant about it. Everyone says it's required but most don't enforce it.

I do already have a pretty good offer from another place where I didn't need to disclose this information and didn't really lose anything but it really surprised me. This happened after I finished two rounds of interview, one phone and one in person and they wanted to move on with an offer.

I'd talked about my current offer and they also asked me to disclose that. I probably could have easily gotten more money with this but really wanted to stick to it this time.

How common is this? Does your workplace let a good candidate you're about to offer a job to go because of this?