Originally Posted by iflyjetz

No shirt. No shoes. No service.
That's been the traditional definition of proper attire in food establishments in the US. I'd argue that the same applies here.

After thinking about this for a while,
1) I would take a photo of the offending party.
2) Tell the concierge lounge personnel to either enforce the dress code or get the manager to come up immediately.

I've grown weary of the 'anything goes' attitudes. And I'd do the same if someone brought an animal or noisy children into the lounge.