Let's face it; this argument is more about the personal preference of the "elite" runner's than anything having to do with the safety of runners. It reminds me of the rule that requires professional golfers to wear long pants in 100 plus degree heat in Texas for the "good of the game". This is about running purists who believe it takes away from the sport and perhaps lowers the standard to a recreational activity. I like to believe we are all competing, whether it is for a top three finish or a Personal Record; regardless of who is wearing an iPod.
As far as a runners safety, Wilmpete, when that car swerves at runners wearing iPods during a race and all of the non-iPod runners dash gracefully out of the way, do you really think the iPod runners are going to just continue running straight ahead listening to their music? No, they/we will likely hear the car and react the same as you because we are used to running and training on roads and listening and watching for vehicles wearing our iPods. If we don't hear the car right away we'll be reacting to what is happening around us; we are not blind after all.
I've been running for many years and witnessed runners who were hurt during races that had nothing to do with wearing iPods and everything to do with bad weather and road conditions. I live in the Northeast where there are races year-round. I've participated in races with snow and ice and driving rain and seen runners hurt during races. If the USATF really cared about a runner's safety they wouldn't allow races in bad conditions; but races go on because most of us train in these types of conditions. I have no issue with proceeding with the race, race directors and volunteers have spent a lot of time setting up the race; and since most races have a charity associated to the race, the charity is counting on the proceeds.
Active Sara, golf is at least ONE sport that does not prohibit a player from using headphones, earplugs, etc during a stipulated round of golf provided they do not communicate information on the conditions (such as weather) which are relevant to his play or otherwise assist the player in his play. The USGA does not seem too worried about golfers not being able to hear someone yell "fore" or avoid being hit by a golf cart; odds seem more likely for that to occur than the scenarios the non-iPod camp seem to dream up. Race car drivers are permitted to wear headphones as do football coaches; and they are allowed in fishing. I'm certain they are also not banned in other sports, but rather, athletes choose not to wear iPods during competition so they can hear their teammates or perhaps another runner closing in; something not necessary for those of us not in the front of the race.
But I do understand these devices have been banned by the USATF and do plan to comply with the rule, as much as I disagree with it, by not running any further road races. I've already passed up several half-marathons I've run for years this past fall and have accepted to participating in virtual runs with other Nike Plus runners. I'm nearly 47 and have enjoyed running road races for many years; I've enjoyed meeting other runners, donating to local charities that sponsor these races and collecting loads of shirts.
However, I am also hopeful that Nike, Apple and other runners can help change the USATF members to overturn this rule in the future. Much like baseball purists who were against Major League Baseball adding a third division to the National and American Leagues and a wild card team from each division to expand the baseball playoffs, the baseball commissioner proceeded with the change for the good of the game (and perhaps more revenue); change can be good. Inclusion not exclusion. 
My two cents.