And what about the safety issue, the whole reason the USATF added this rule? We found out after Grandma's exactly how much of a difference an enforced headphones ban made for getting emergency vehicles where they were needed and for getting runners to hear instructions at an event that's relatively small compared to NYCM. Imagine if emergency vehicles needed to get on the course with 30-some thousand people, many who can't hear the vehicles coming because they are plugged in and tuned out or if an important instruction needed to be given while at least several thousand were tuned out.
Sure, it's difficult and probably unreasonable to enforce the rule 100% but, by saying you're not going to enforce it at all because it can't be enforced 100%, you're basically saying that a rule that you're mandated to enact and enforce for safety reasons doesn't matter. Doing this after being given the honor of hosting the Olympic Trials is a slap to the face of the USATF. Enforce it to the best of your ability and the risks associated will at least be greatly reduced, which is the whole point of the rule in the first place.