League Against Cruelty To Dogs

A strange group apparently devoted to ensuring the welfare of dogs in Ankh-Morpork. They apparently hold Vetinari in the lowest respect, addressing him in their regular complaint letters as "Cur". These letters have worse spelling than that of Carrot Ironfoundersson, and are rather wet. The medium of writing is crayon. The grubby, much-folded scraps of paper are pushed under the door of the Patrician's Palace most nights. Apparently no one is seen. Could it be that a couple of vampires are being employed by an obviously poor group to ferry messages?

Strangely, Gaspode occasionally sits on a street corner next to a damp chalk message asking for people to help him, along with a grubby cloth cap for donations. The spelling seems to match that of the League's letters. For some reason, Gaspode is suspected of writing the message by holding the chalk in his mouth. What sort of cheating dog would use such an approach in an attempt to attract aid?