I can't remember if the British troops wore flak jackets in Northern Ireland. I know they found they got a better response from civilians if they 'dressed down', so to speak.
Which reminds me of an old British Army officer recruitment advert, where you are watching some African warlord minion shout at you from the first person perspective, waving his AK in your face a checkpoint. The officer takes off his sunglasses, and the guy calms down and actually starts to sound reasonable.