Can My Employer Have A Dress Code That Disallows Medical Alert Jewelry?

I work at a very well known coffee/donut shop. A few days ago, on the last shift I worked, I noticed that one of the signs by the back hand sink was describing our dress code. There were things like no fake nails or nail polish, no necklaces, no bracelets. But that last one struck me, be cause next to that it stated, this is a quote, "This includes medical alert or religious bracelets." And as far as I am aware, that statement alone is against ADA policy. However, I have no idea what to do with this information. I could really use some help because I want to go to HR, but my manager already doesn't really like me and I've only been there for a little over a month. Any help is appreciated!