And although I know better than to take my research from here, according to Wikipedia:
However, coolie is now regarded as derogatory and/or a racial slur in the Caribbean, Africa, Oceania, North America, South America, Southeast Asia and Europe – in reference to people from Asia.[a] This is particularly so in South Africa, East Africa, Trinidad and Tobago, Guyana, Suriname, Jamaica, Mauritius, Fiji, and the Malay Peninsula.[5] In 2000, the parliament of South Africa enacted the Promotion of Prevention of Unfair Discrimination Act, which has among its primary objectives the prevention of hate speech terms such as coolie (koelie).[6]
en.wikipedia.org/wiki/Coolie
I think I land on the side that she shouldn't have worn it if there is any question - there are many inoffensively named titfers!