Before changing the max_blocksize constant, we should know what happens to the BTC function at (and over) the 100% limit of the tx/block variable.
we already know what will happen
transactions wont confirm and there will be a backlog ,it would render the currency unusable if we had to wait hours or days to get included in a block
localbitcoins would die ,retailers would stop accepting btc for coffee or food etc because they cant force a person to wait all day until the transaction gets a confirmation
miners would include the highest paid transactions so it would mean higher fees for everyone to use btc efficiently and the price would be all over the place if you accepted $1000 in btc for a laptop it might be worth $900 by the time the transaction gets from the customers wallet to your wallet to the exchanges wallet etc
this would be huge to giant retailers
bottom line is we dont need to wait until it breaks and have a mad panic to get it fixed
do you drive your car until the tyres explode or replace them before that happens ?
I trust both my car's and tyres' manufacturers test every model to find out exactly how gracefully or suddenly their products' safety features degrade in the event of predictable and inevitable events like tyre explosions. Stress-testing is Engineering 101.