rather than snort in other people's ears every 30 seconds for half an hour?
Yes, of course, sometimes people run out, or forget them. But seriously I can only remember a handful of times when I have had no tissues on me. They're just one of those things I carry around with me, like money, and keys. Whereas everyone who sits next to me on the train at the moment just snuffles juicily at me. They don't even try to do it serreptitously. I harbour dark suspicious that they never carry tissues.