True, but that assumes a degree of technical fluency, which American courts have repeatedly failed to demonstrate.

I think it'll "hold up in court", for certain definitions of "hold up" Judges are not stupid. No single piece of evidence is 100% reliable and enough to get a conviction. A MAC address will just be another piece of the puzzle. Judges will familiarize themselves with what they are and that they can be spoofed, and will take that into account when evaluating the evidence.