I also will probably use the Chain Johnny instead of the travel bag on day trips when my wife and I will slip the folding bikes into the SUV to reach our departure point. It will be a lot faster than using the bag that completely covers the folding bike.
White Lightning as a multiple-paragraph description of the Chain Johnny, one of which states:
The Chain Johnny uses a rip-resistant, 2-ply rubber/nylon material which protects the inside of a car much better than old-school methods such as towels or rags. It is also water resistant to protect the drivetrain itself when transporting bicycles on vehicle-mounted bike racks or storing them in the garage during the winter. Apartment and college dorm dwellers are also using the Chain Johnny to shield their greasy chains when storing their bikes indoors.Sometimes I toss in a small ditty bag or two into the bike bag, and I can feel comfortable that it won't come out greased up from the bike's drive train.
I'd keep the instructions handy for installation because there are some recommendations for easiest use as to what gears to be in and the steps of installation. The website also has online instructions. I plan to photo the instructions so I'll have them on my smartphone when I travel.