Whilst I'm in agreement that the elderly don't have to live with the decisions they make, I don't think this is the answer. After all, why not say babies have the highest weighting as they'll have to deal with the fallout for the longest.
So the simple answer...make the elderly work menial jobs nobody else wants until they drop dead. This solves their other complaint that too.many foreigners keep coming over and working in farms. Problem solved. Or develop a "Logan's Run" type system instead.