That wouldn't work because Zwift championship races require a separate power meter on the bike in addition to the smart trainer. If you just strap an electric motor to a separate bike then the power meter numbers would be all wrong, especially if it supports ANT+ cycling dynamics. You would need a reciprocating machine that actually pushes the pedals, like what power meter manufacturers use to test their own products. So it could be done, but would be difficult and expensive.

In the end though it's impossible to be 100% certain that the data stream coming in to the server is an accurate representation of a real human effort. The whole thing is kind of silly.