How to test an air intake restrictor

I love the simplicity of the scrutineering test that appears to have caught out the K plus K Motorsport Saleen at a recent FIA GT round:

The S7R was thrown out for failing to conform with the regulations when its engine failed to stall when the restrictors were blocked during post-race scrutineering.

Block the intake at the restrictor and see if the engine stalls. Brilliant.