I agree, there have been threads on this before,
http://www.pprune.org/forums/showthr...memetic+weight
My suggestion was to weigh passengers and thier luggage at check in. Make it attactive by rebating "unused" allowance as frequent flyer miles - or carbon tax credits!
I'd also like to see have duty free ordering in the terminal with delivery at destination - which gives you something to collect while you wait for your luggage to show up and now I think about it agian would spread out the passengers so the flow through baggage claim and imigration could be smoother.