Interesting. I worked at a large bank a while back and they had a use it or lose it policy. Either the law recently changed or they were out of compliance.
I don't think it is a recent change. The reason I am familiar with it is my current employer tried to pull this one--I showed them the law and they backed down thankfully.
Also, don't give up on old wages. An employee at a former employer filed a class action lawsuit (somehow I got attached), his hardwork resulted in an $8k check that found its way to my doorstep. ;)