My son dresses pretty normally, but I worried the last time we went out on a warmish but rainy day and he insisted on wearing his winter parka - I thought people might see him in an unseasonably heavy coat and suspect him of concealing something. But there was no use arguing. I did have him pick out a lighter weight jacket to wear in similar situations next time.
My son also is very impressed with brand name clothing, but I have found that visiting the thrift store regularly I can supply him with the brand he likes at a reasonable cost. He of course just thinks I have washed things before putting them in his closet.