I wondered this as well because I have/trained service dog rejects and I wondered "where do they go?" I mean I trained both mine to go anywhere on command, I'd just feel bad having to have someone else take out that trash...
I have a service dog and we went on the Magic. They had a plastic children's pool with sod in it on deck 4. My dog is small. There was a larger dog on board and they did not clean up after said dog. Ours was put off about going in there obviously. We ended up cleaning it all the time which was annoying. He was happy to get off the ship and find his own spot!
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