Another to add to the message-found-on-doorstep list: white powder.
"Police today sealed off an area around Labor Senator David Feeney's office after suspicious white powder was discovered on the doorstep. A staff member made the discovery about 9.30am. Sources said it looked like “a pile of icing sugar” or flour and some suggested it could be a result of factional warfare." They don't, for a miracle, call it a mafia-style message, and they don't say what it's supposed to mean.
Honestly, this is becoming like the language of flowers.