When you save your ally from Caitlyn's ult.

then you step to far over and miss her ult http://24.media.tumblr.com/tumblr_m672bsqWvk1r81219o1_500.gif

And the enemy has a spell shield

Riot: Well time to disable her until the bug is fixed

2 days later

Riot: Well we fixed the bug, now a new bug has a appeared, time to disable her until the bug is fixed

it won't happen anymore

We dont need to dodge caitlyn's ult because Riot already did it for us with the disabling!