Did you ever see the marks passing hobos used to make on doors to indicate kind ladies and mean dogs, during the Depression? It's done in Mexico, too, but for fellow thieves. Apparently los ladrones are more organized than I thought. The Club Cruceros website in La Paz published this illustration as a PDF, borrowed from the forum of the Guardia Civil. Makes me think my next dog should be a big one. Or maybe I should just find some chalk and mark it up myself, like those fake burglar alarm stickers.The marks that really give me the creeps are "Older woman home alone all day" and "Kids home alone in the afternoon."