Here's a story by NPR.
I just don't want anyone that reads this, especially greeting card merchandisers because they are on the lowest pay scale in this industry, to think that they cannot discuss with anyone they want what their salary or hourly wage is. That is the very reason that the greeting card industry can get away with that kind of pay in the first place!
A company cannot, by federal law, require that you not discuss your salary. However, they can require you not to work for their competitors, now and for a period of time after your termination. I am a merchandiser also, working for Acosta currently so I know about retail non-disclosures. I can't imagine AG field merchandisers, or even their supervisors or even THEIR supervisors being subject to any kind of non-disclosure agreements that have any meaning. Are you a designer for the cards or a high-level manager? Even so, they cannot require you not to discuss your salary!
I don't think any one needs to know what any one else makes.