I can tell you my experience...this was around 2008-2009.
A few years ago when the federal minimum wage was raised, you did not see a pay increase if you were already above the new minimum. I had tms the had been there for years and had started out at $5.75 or something right there abouts. When the minimum got bumped up to $7.00, everyone that was under $7.00 got a raise that took them to $7.00. If you were over the minimum, you saw nothing. So we then had a lot of people quit because new hires for Salesfloor and cashier were making 7 per hour while some of the seasoned tms were only making 7 as well. It pissed a bunch of people off because it made your previous merit raises not matter at all. You bust your ass for a company for feeble pay increases and then minimum wage goes up, and while you're making more than you were...your experience, past performance, and work ethic count for nothing.
But that's just business as usual.