Translation:She wears hats.
I believe they are only specifically pluralized when you add their counters or when there is a general amount word (sorry, I don't really know what these are called, but see the third and fourth examples.) Otherwise it is left up to the context and the listener's interpretation. Example: それは本があります。 There is a book. or There are books. (Unclear which it is) それは本が3冊あります。 There are three books. 冊(さつ) is the counters for bound objects, usually books. それはたくさん本があります。 There are many books. たくさん means "many" or "a lot" それはたくさん本がありません。 There aren't many books.
I hope this helps! Please correct me if I got anything wrong.
So, the context for this that played in my head is that it's the first day of school, everyone in uniform...and this girl walks in wearing an oversized sombrero, and casually takes her seat. Someone who doesn't know her stares, looks to his friend, and the friend (who was in class with her the previous year) shrugs casually and says this.