We have an auto feeder for their dry food that has a removable metal bowl beneath the spout. When the metal dish is in place, all the kibble pours out into the bowl. When the cats think the food is overdue, they will tap the metal bowl out of the way to get attention or wake the machine up or whatever cat reason...and the kibble bounces off the hard flat plastic surface and half of it spills onto the floor where the dog will gobble it up.

Sometimes I put the bowl back in place and sometimes I wait and see if they'll learn the lesson on their own.