Yes! Mmm, well, sort of. I mean, To make this analogy really work, imagine if they played the national anthem at your workplace, and you were required to stand, remove your hat, and place your hand over your heart. I think this would be a little weird, and the employer would have a tough time defending that requirement legally, if it were called into question in court. It's not like the football players, in this case, are trying to distribute pamphlets or give political speeches during their time on the field here, it's a symbolic act of omission. But, on the other hand, these symbolic acts of omission are, as it appears, costing the NFL some amount of revenue, so, maybe there is an angle to work it that way, legally, but I think, at the very least, it'd be unprecedented legal ground, although I'm not 100% certain of that.