Earlier this morning, the New York Times reported that on Tuesday, General Motors sent a special memo to Chevrolet employees at its Detroit headquarters politely (sic) suggesting they ditch the "Chevy" moniker for "consistency" of the brand.
The Detroit automaker responded with an official statement which more or less supports the use of the 'Chevy' nickname by consumers and fans alike (as if GM could do anything to stop them...), but says nothing about its employees. That said, it appears GM staff are indeed being told to avoid saying Chevy when referring to Chevrolet.