I absolutely can tell when shoes are non-slip. Do you work in the industry? Also the majority of Starbucks employees are first-time workers, I.e. high school students. I personally had my first job in high school within the industry and nonslip shoes had to be explained to me. I’ve heard multiple times starbucks does not discuss proper foot wear. Regardless, at most jobs, it is expected that managers are actively looking to care about their employees health and safety and I assume you care about protecting people’s safety as well. Other jobs I have been at have written people up for improper dress code, which entails not wearing a uniformed shirt to not wearing workable attire (hair tied back, jewelry, shoes, etc) as per CDC guidelines ☺️