It seemed like a good idea at the time...
tl;dr - Just because you can skin something does not mean you should.
tl;dr - Overview of GPU Override Observations
tl;dr - An actual strange rigging trick involving Euler rotations.
tl;dr - Directional constraints with deliberate connections.
tl;dr - When all you have is a hammer, sometimes you have to make your own nails.
tl;dr - Delete your blendShape's targets' geometry.