There is a little give at events Ewan.
But sorry you took the **** at FWSmash2003 i was told
Roaming Robots, FeatherWeights.org both give a little which is 200g. Its in the rules for Robot Wars that a Heavy Weight has to be 100kg and no more. But allow a 1% scale error which gives them 101kg true weight limit. 1% for 12g is 12.125kg , but we round it up to 12.2kg as its an easy number. (And Jonnos scales only go to 2dp) hehe.

12kg is the limit for Feather Weights. Like Ed said, it is a challenge, but thats part of building the robots.

The extra 1.6kg to make it ti 30lb (13.6kg), thats a 24v Nicad 3000 pack. Thats a Mag motor. Thats a 600g Co2 bottle, thats about 2mm worth of Ti all over a feather weight.
Think Feather Weights need to stay at 12kg.

Mr Stu