When I was growing up, we had a dog. Not the brightest dog in the world, but loving and loyal all the same. He could sit, stay, eat things, get the paper...you know, dog stuff.
We (and by "we" I mean "my dad") trained him to bark when he needed to go outside for purposes of elimination. This seemed to work pretty well.
The Wife has a dog now. And so, by extension, do I. The Dog is fairly bright, can sit (sort of), stay (sort of), find people who are lost in swamps and hotel laundry rooms...you know, dog stuff.
We (and by "we" I mean "The Wife") doesn't like the idea of dogs barking to go outside. So we trained her to signal that she wants to go outside by ringing some sleighbells hung by the door for that purpose. Except sometimes, we take the sleighbells down so we won't be disturbed while we're sleeping. And then we forget to hang them back up.
The Dog (remember I said she was bright?) has a backup plan in this sort of situation. Just tonight she came over to me as I was sitting at my computer, lay at my feet and gazed up at me with adoring puppy-dog eyes. Eyes full of trust, full of love, full of dedication. I smiled back down at her.
Then the smell hit me. An SBD that would have made Kaiser Andy proud wafted up and singed my nosehairs off.
Me: [gasp] The Dog, do you need to go outside?
The Dog: Why yes, why do you ask?