Get a telescope, go to NewYork, look east. If you see europe then light travels in straight lines, if you dont, its becasue it travels in a curve.
Space probes would see the light being pushed away from earth, you still haven't addressed that. You may aswell just say the light ceases to exist. No, the metric changes so that in the same unit time it appears to be going the same distance. I was a bit unclear about that, when it goes down from the sun and is being pused back, the metric get longer, and above the sun moveing away from the earth it gets shorter. Traveling the same unitmetric per unit time.
Hang on, before you said it was places on the flat earth that the metrics change, now its places in space where ever this "pushed away" light goes. So if two space shuttles where above the earth and one went to where this "push away" light would be, would this shuttle become invisible? could it send radio messages or would that get pushed away too?(And before you start on that, in Black holes the unit Time is supposed to get longer, mind you they cannot prove that its not the Unit metric getting smaller)