What is wrong is that people should be aware of the technique used. Adding resistance to the ground leg is a very common technique that should not be confused with varing the supply side.
A 2003 Chevrolet Impala uses the same technique as the Sebring in this thread. the variying the ground is widely used with GM and has been for 25+ years, why not explain the circuit like it really is?
When people know how the circuit works it is easy to explain why they only have high speed, the reason is all other paths to ground are gone except the direct one on the high speed circuit.