We have had bags get soaked on the tarmac and in our own boat on the way to the house. We have found three good ways to prevent that: Pelican rolling carry-on and briefcase, Action Packer inside a large duffle bag, hard-sided suitcase with rubber gasket.
The last are not easy to find, but can be ordered. We have a venerable set of orange plastic ones that have been around the world, but predate TSA locks. Now we have Samsonite Spinners with TSA locks. The key is to get the ones with clamps and a gasket, not a zipper.
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