I'm curious what you meant by appearance matters? I did purposely mention my work uniform in my OP. I think my work group is known more for carrying fakes than not being paid well. But I did wonder if my uniform might have something to do with it? I just find the whole thing odd. It appears it doesn't happen often due to the lack of replies on here and most ended up being about someones Dad.
Quality of service, treatment, and SA attitude may matter based on the client's appearance and what they're wearing.
As for your uniform, maybe, maybe not. Hard to tell because it may be a stereotype or generalization or the SA's personal bias.
My work clothes definitely gives the bias or assumption of having money, so it doesn't matter if I wear my regular clothes or my work clothes.
My SA at SL told me a construction worker came into the store to buy something for his significant other. Which was cute but he did truck in mud from his boots all over their brand new rug. My SA wasn't the one helping him but I'm sure that would even put me off. (not saying you would bring in mud to a store, this is an extreme example that just came to mind)