I was reading Wheeler & Taylor's Spacetime Physics. The authors mentioned about tidal effect, as well as all physics laws are same in free-float frame.
I am left wondering if tidal effect will make the laws different in a same reference frame - suppose two people are in same free-float frame under the influence of a black hole; however, one person floats (unfortunately) right next to a black hole, and another person floats too, but with super far distance from the black hole. Surely, the former misfortunate person has a very different experience than another - he/she probably will even be killed due to the tidal effect!
Consider another experiment: suppose a train vertically falls into the Sun. Let there be two floating people in the train. One at the top "drops" one ball, another at the bottom "drops" another ball. And they observe the balls. They all claim that the balls are perfectly in inertial frame - they do not find the balls accelerate. But overall the distance between two balls increase due to the tidal effect! Can we say (is it plausible) that "the train is a free float frame"? If ONE person (either at the bottom or top) drops TWO balls instead, he will never observe the distance between the two balls increase!
I am left wondering if the physics laws are still same in this case? Would it be more proper to say "all physics laws are same locally in all free-fall frames"?