That may be true, but would "Mom" feel safe with the under 18 teen being in a different unit that could be on a different floor or even a different building (depending on the resort)? Maybe I'm old fashioned, but two teens staying in a studio unchaperoned could be a recipe for trouble even if one is 18. Now if the 18 year old wanted to be in there with other 18 year old friends, that would be a different story.