Another Ballast Weight Question

[Snrizedstr]

I have a 2012 21 VLX. 
Why is there a 75# weight limit placard on the rear lockers. 
I see plenty here running 400 # and more sacks in addition to the factory ballast tanks. 
Has there ever been any problems with that kind of locker use, is this just a factory way of releasing themselves of extreme stupidity? 
Curious about this before I make it a common habit. 
Thanks

[granddaddy55]

i ran 850’s in a 14 a20, reinforce engine dividers with wakemakers kit or some u channel you cut 

[Zippymbr]

I have 1100 in my rear lockers of my 2007 23 LSV I reinforced the locker walls with a wake makers style kit I made.