Many firms require job applicants to tell them either how much money they're making at their current jobs, or how much they want to make at the job they're interviewing for.

Citation needed as this is actually illegal in many jurisdictions. They may ask, but they may not require disclosure.

What do you think? If you were applying for a job that you wanted, and the company said "You must give us proof of your current or most-recent salary or we will not give you an interview," what would you do?

Next job please. I wouldn't want to work for these jokers.