If the motors are open loop (as these ones are) there is no home position without an external limit switch somewhere. But the machine may not always use that location as the "zero" coordinate, it depends on the application and how the controller is programmed. However the G53 zero-coordinate isn't the same as its home position since one is a physical location which never changes whereas the other is a software location.
The best example is that many mills have their Z-zero position pre-defined to be a couple inches below the highest Z-valve (limit switch). That's up to the controller though, it's just done that way to establish a baseline for G53 Z-zero always being the toolchange height.
Remember that cutting power in any direction to an open-loop motor wouldn't be possible because it'd create a mis-match between the programmed position in motor pulses and the actual linear position, because those open-loop pulses never made it to the motor. The controller assumes every motor pulse is indeed causing motion (of course that's not always true since the motor can miss pulses or encounter problems due to a crash) so cutting power would be a nono.