Many people who have high ranking membership may be on their way to or back from vacation, hence the shorts, t-shirt etc. The line should be drawn at bare feet and singlets - they do at the movies! Thongs (those for feet, I mean) are fashionable at the moment, so it would be difficult banning this. It's the behaviour that gets to most people. It is supposed to be a quietish place. There are restrictions about mobile phone use in this many lounges for this very reason.
What really annoys me, besides louts and adults acting like they have never experienced a decent place before, are those who bring in their screaming, running, protesting children. I was of the understanding that a QC member (or any other club for that matter) could bring in one guest. Does this have an age limit e.g. above the age of 12, and younger than that are free? Not everyone is in the mood for their cute little darlings, and joining the club is the primary reasone for getting away from this type of behaviour.
All clubs that charge a joining fee should make this very clear. I waited for a plane in the general lounge recently, and I noticed how much more well behaved and considerate the people were there than in the club! Mmmm - it seems the club is where the brats are.