My view is that I would rather the 16 and 15 yr old be in a lounge than roaming the airport. Obviously it requires the 16/15 yr old to have a certain maturity. But a lounge is the safest place in an airport to be in my opinion.
Also there's the argument that the sterile area past security and customs screening at an airport (and then past the sometimes more invasive screening by lounge dragons ) Is one of the safest places one could be...