I actually do have a simple backup just in case I ever have a problem filling my Gaslow tanks in foreign countries. I have one of those small Cadac barbecue things. It's in a small case about eighteen inches square. We used to take it in summer (obviously) but I now carry it all the time, along with three cartridges. It's reassuring to know that, in an emergency, I can stand it on the top of the grill's glass cover and boil water and make a simple meal or even fill a hot water bottle if it's cold at night!
Fortunately, I've never had to use it, apart from barbecuing, but it's nice to have the reassurance of a backup.