What I expected to happen was...:
A redstone signal to disable a hopper.

What actually happened was...:
Hoppers are always enabled even when powered.

Steps to Reproduce:
1. Place a hopper
2. Place a lever or redstone block beside it.
3. Flip lever and throw something into hopper (see that it is not disabled as it should be).

Proof: http://youtu.be/jIceCz2QQzI