or yank it out while you're waiting to show your passport which happens before you talk to animal control and out of their sight. Stuff in a bag. No one will know and no one will care. Except the animal control person. Who probably doesn't care either and may or may not decide to enforce the rules. Plus they can't see you at all when you're standing in the immigration line.
I also have another really superb tip,(even if I do have to say so myself) for travelers with pets and dealing with the accident potential in the case of not having enough time or opportunity to get them to a pet relief area.
Buy belly bands, line with a kotex and you are all set. I bought one of these for one of my male dogs who started marking territory when I brought two new puppies into the house last November. It fixed that problem after a couple of months and he doesn't need it any more. But in the process, I realized that this is a wonderful solution for any kind of situation where your pet can't be let out to urinate -- like long plane trips or hurricanes. So I now have one for all three of my dogs. Put little 2.5 lb Bruce in one for our trip to California two weeks ago and never had to worry about him the whole trip. He didn't use the pad but if he'd had to go, it would have taken care of the problem so no clean up necessary.
I would advise buying from this source: bellybands.net
Sure you can make them yourself but these are done just right in terms of being soft, comfortable and fitting all 3 of my dogs, all different sizes, just right. They are also quite cute and when worn with a sweater over them, looks like the dog is wearing rompers.