My child can wear whatever he wants, I don't care and I don't want to fight about it, seriously - and he is only 2 as well. So far we haven't had this issue, but I really don't see it as an issue if it does come up. And honestly there are times I just leave him in his jammies and we go all sorts of places. There's no way I can stop my child from wanting to wear jammies to the store anyways, because I will wear my jammies to the store as well (and I'm talking about polka dot / dream girl / crazy colored jammes!)
I've never been one to care about what society thinks they can dictate I should or shouldn't be wearing, and neither has my DH. We were skateboarding punk rockers in H.S. with multi colored hair, tattoos, crazy clothes, etc anyways so I can only HOPE my children have just as much creativity when it comes to their clothing choices too. I believe our clothes, and our hair, are ways to express ourselves and our creativity. A child can be outrageous or creative for only so long with their clothes choices anyways before they need to grow up and be adults and go to work in their suits or ties or khakis or highheels, etc.
I remember at my Grandpa's funeral, my brother was lik 3-4 or something. My mom had a suit for him to wear but he refused to wear the dress shirt. So he went to the funeral in suit pants and coat with a tie dye t-shirt underneath instead. He was fine, the world didn't end, no one made negative comments, and he isn't emotionally disturbed now that he's an adult.