The reason SQ keeps everyone but their own top tier and First/Business passengers from the Silver Kris at SIN is because STAR alliance, unlike oneworld, only has two tiers, not three. It has long been a complaint of us STAR Snobs that life would be much better if the riff raff could be eliminated by the creation of a new top tier [PLAT since SILVER and GOLD are the current tiers]. This way only paying First Class and top tier passengers could gain entry to the top tier of lounges offered by a few of these carriers. If you think there are too many EMERALDS, just consider how bad STAR is with all those GOLDS running around, of whom maybe 2% are top tier members of their own programs, and should rightly have their own super elite tier. Long live elitism as long as I can be in the top tier of it!