My nice shampoo turned into a science experiment on a road trip

I drove from Columbus to Chicago last fall with a fresh bottle of my favorite sulfate-free stuff, and the altitude change blew the cap open in my duffel. The entire bag smelled like coconut for 2 days, and the clothes I had in there felt greasy no matter how I washed them in the hotel sink. A friend suggested I transfer products to smaller squeeze bottles with locking caps, so now I keep a 2 ounce travel size for every trip over 100 miles. Also, I learned to wrap the bottle neck in a rubber band and a plastic bag before tossing it in with my stuff. That little trick has saved me twice since. Does anyone else have a horror story about product leaks during travel, or a better container system that actually works?