'Find out' needs some clarification. Why can't I create a million network nodes which I control that either:
a) approve my conflicting transactions
or
b) 'disapprove' genuine transactions
and then just steal the collateral of genuine participant lockers?
Your voice in the network is proportional to the amount of money you have (POS). Check out the locker selection function for more details.
So, as an attacker with large stake, all I need to do is vote against valid transactions and just harvest all their stake? Neat.