I really don't see them letting the agreements they still have for G4 to go to waste. Layoff notices with a state's labor department doesn't mean the channel is going away. They could easily program it with two guys and a control room in New York.
The Cablevision filing is to the CT Public Utilites Regulatory Authority (formerly DPUC). Cable providers are required to notify the state when and why they make changes, and has nothing to do with layoffs.
Here is Cablevision's exact language, "Effective Thursday, October 10, 2013, NBC Universal will cease to air G4 in both standard definition and high definition"