In Africa, where there are dreadlocks, there are white tourists being preyed upon

Guides, maps and tourist fact-boxes often adopt little pictorial symbols: shorthand icons that signal key facts or recommendations. A tiny canoe, and parasol, for example, indicate boating facilities, plus a beach. But less common have been warning shorthands designed positively to identify an unpleasantness or something to avoid. How about (for instance) an overflowing dustbin with wavy lines above it, for instance, indicating ‘smelly’; earmuffs against a hotel’s name, as a ‘noisy’ warning; or a trouser pocket with a wad of notes sticking out: ‘pickpockets operate here’?

Since returning last month from Africa, I’ve been ruminating on the need for at...