I'm getting married in a few short months (and I'm making the 6 kilts for the wedding party). I know how sad I would feel if anyone in the party said that they were insulted I was asking them to wear a kilt. Be there for your friend regardless of the dress code -- or don't be there at all. (Now we got engaged just before halloween and when we asked my ring bearer to do his task this very intelligent four year old informed me that "I'm going to be a wizard not a bear. I don't want to be a bear because wizard's are cooler." when I explained he said "But I don't want to be a bear. I want to be a wizard." Now that halloween is past he is looking forward to it (and I showed him what (our) ring bearer will wear, and he thinks its pretty cool)