Yes, I've been in some of the situations, fully nude and undraped.
The Korean Spa I used to go to was one. I had massage and exfoliating scrub done several times in the men's locker room / sauna area. It was slightly partitioned off, but not much, so that most guys could pretty easily see what the scrub and massage was like. I had that done probably a dozen times or so, but not in about five years now.
Another time was back when I used to travel in Central America from time to time. I was in the tourist city of Granada, Nicaragua (a lovely city, BTW). The hotel staff recommended a particular place in Granada for a massage. The massage was given by a man who was blind. It was done on an outdoor, second floor patio, surrounded by dense foliage, so that it was private. He was an excellent masseuse. I only had that done once.
Generally, I prefer female masseuses, but these experiences with male masseuses were very good. We should probably have a discussion thread in Zity about Korean Spas. I'd be particularly interested in hearing women's experiences at Korean spas. In neither of the two situations above did I ever feel uncomfortable being fully nude and undraped.
Then there were my experiences with Brazilian waxes, but that's for a whole other post, maybe even a blog post.