This isn't even remotely true.
If anything it should be better enforced, Koepka not getting penalized was chickenshit. Players aren't watching live TV coverage while playing - they definitely don't know what club a playing partner is hitting all the time, and when a shot comes up 10 yards short they absolutely want to know what the player just hit. Let's say the guys are friends like JT and Spieth - JT turns around after coming up short and signals 6 iron to Jordan, he switches clubs and flags it. It's just straight cheating.