I hate dogs, don't care for sob stories. That said, the trailer reminded me of the first time I dogsat Juno (Junior's dog), and let her take me for a long walk. It's cold, February or March, maybe 35 or 40°F. She got a random thought that it was time for a swim and leapt off a footbridge into a pond. Without opposable thumbs, there was no way for her to climb out, and I couldn't drag her out by the leash, so I had to go in too and push her back up. She understands now that walks are for walking. No swimming unless I say its OK. I think the 2 mile soggy, cold walk home reinforced the lesson pretty well.
Edit: In her defense, she part retriever, and there was a goose she wanted very badly.