Wrong handflying
I did diversions before and more than one. You are right that you will not the only one. That is why the regulations (in my company, I guess there are also regs by JAR Ops) demand that you arrive at the destination with at least 30 minutes of holding fuel in case of Low Vis Cat3 conditions. If unforeseen weather conditions arise inflight planning should maybe call for a diversion before arriving MDF at the destination.