Spoken like a man with no daughters. There is no dad on the planet who would not be concerned about a 30 year old naked man in a hot tub with his 15 year old daughter.
My daugher, yes. But see my post 35. Also, I have three daughters, the youngest of which is 22. I have learned that not all 15 year old girls are created equal. I first learned this when I was 13 and my 15 year old female cousin was selling "peaks" to me and my younger male cousins for a nickel. By "peaks", I mean third base.