For the sake of ???

Yesterday I was at the Suntec City. As usual I went to buy my favourite sugarcane juice from the stall which is located near the cashier at carrefour level 1. My perfect choice will always be sugarcane juice with sour plum. However, when I was buying the sugarcane juice, I noticed the 2 servers (1 squeezing the juice and 1 being the cashier) wore a mask while serving customers. You may think this is the perfect hygiene level. Guess what? My god, both of them are wearing the mask for 'show'. Why did i say that? Its because their mask was wore not to cover their mouth but was wore to cover their chin. I think they are just defeating the purpose of wearing a mask or should I educate them how to wear a mask or should I console myself because the IMF is over? I wanted to tell them off but was being stopped by my friend who told me to let them be. YES, I am going to let them be and telling them in my heart, one customer lost PERMAMENTLY.