The cases where I wasn't paid, my employer has a written agreement that I am temporarily taking a salary decrease in exchange for a deferred bonus with no date or time limit on the bonus so it's not quite that clear cut.

I'm not a lawyer though, I'm sure if I want to get dirty I could find a way to bend it to my will but I'm not eager to get in the mud, I just want to build great software and get paid a fair salary for it.