As a countering opinion, though I feel odd wearing my hose without a sgian dubh there are times when I leave it off, either for practical purposes (such as airports) or out of respect for others. For example, I am not christian and do not normally enter churchs but as a scout leader I encouraged the spiritual growth of the scouts. We all attended chapel and always followed the tradition of leaving our knives outside the chapel at camp. It was a non-denominational space considered to be a place of peace and trust. We actually had a post just outside the entrance you could drive long knives into and a tray for folding knives. Just saying that sometimes one should honor the tradition and rituals of the place you enter.