I guess what I am talking about is wearing the kilt to more formal, non-Scottish events, like say a party or a graduation from the men's initiations I am involved in.
I have seen it done, but I can't say that a Utilikilt looks at all appropriate for dressing up. They are the "cargo pants" of the kilt world. If you would wear cargo pants to these occasions, and consider it appropriate, then by all means wear the UK.