With Diminishing Returns, how is stun locking viable - especially if the target has a trinket to remove the initial stun? From what I understand, Cheap Shot and Kidney Shot are both in the Controlled Stun category. I would think that if the initial stun from CS were broken, you'd only have two - maybe three - CP's, which would translate to 1.5 or 2 seconds of additional stun length with KS. That's not much of a stun lock...
And the break in stun could be a fatal one depending on the target's class/build.
http://vanilla-wow.wikia.com/wiki/Diminishing_returns