What nation of people don't wear shoes?

When I was at Kuala Lumper airport there was a group of about 10 men, obviously travelling somewhere. They all had on matching outfits and looked very smart. I was fascinated by them as they all had on knee length sarongs and bare feet. I thought I was seeing things at first. It seems highly impractical to walk around an airport with no shoes on. I know some religions don't wear shoes inside, but I didn't think an airport would count as its not anyones home. I wonder if they walk everywhere barefoot, even city streets. I just wondered if anyone knows what country these people may have been from and what religion they may be? I didn't see anyone else in Malaysia dressed like this, so I don't think they were Malaysian.