Aircraft Mfrs make aircraft light because they fly better and in order to sell them. Individuals make them light because they perform better! If the powers to be whether that be FAI or AMA wanted to make a cost control rule they should make a "minium" weight rule. Then it would make sense to have a weight rule and provide the man-power to enforce it. Anyone that doesn't believe that needs to take a look at the performance envelope of the newly designed IMAC aircraft flown in even the lower classes, much less the top class.
If we are going to pick and choose rules to enforce the weight rule should be at the top of the list to compromise on.
Dick
PS: Sorry about the slight thread creep but it goes straight to the requirement of weighing all aircraft after every flight.