User blog comment:Vietphro/CB1 - Caspian, the Whirling Blade/@comment-7709681-20150319013042/@comment-7709681-20150319025425

The thing is, blinks once commanded have no travel distance to target the unit, unlike a dash, thus, a unit should bypass the stun's trigger if they blink. Don't feel bad however, you can still affect units with dashes and delayed blinks/teleports (TF, Fiddlesticks, Shen, Urgot, etc.).

However, another option is that the stun has a delayed activation (1s is enough) once it detects the target's movement, such way champions with blinks can be affected aswell.