They're not bloomers and they're technically not panties. The Japanese call it an underskort. Its like underwear to go over your panties when doing something that will likely have your skirt fly up like cheerleading or tennis. To make a clear visual distinction between underskorts and panties, they're made with extra frills as though to say, "See its not underwear. It wouldn't be so frilly if it wasn't meant to be seen."
Tagging would be a bit tricky since they're really not any different from frilly panties. But if you see extra frilly underwear on cheerleader or tennis girl, you can be sure its an underskort.
