IO540
I can assure you that in the UK being in a pilot uniform is only going to encourage the pond life that run security to make your life hell, they like nothing better than to turn out the contents of a pilots (preferably a captain) bag and make a real song and dance about finding the smallest item that they can deem to be prohibited (usually only by local rules not DfT rules)
In short the more status a person has the more they enjoy making life difficult.