It does work, but yields varied results. A lot of the time the edge is too jagged to attempt to fix. It works best if you have a glass cutter and can place an initial gouge where you want the lip of the glass to be. (Since glass is crystalline, the cut line will propagate into the material with the temperature change. Still, unlikely to be perfect.)
Two ciders please, I'm thirsty!
On deck: Soon Cider
bottled: Old and dusty something rathers
Kegged: Carbonated Water (enjoying home made soda syrups)