I used tire liners for years and found my rate of flat tires went way down. I often had no flats on tours lasting hundreds of miles.

People always says that tire liners cause flats, but that wasn't my experience. I did trim them and then sandpaper the ends to make them as smooth as possible. In addition, when I travel with my bike, I have to remove the tires from the rims. This meant that the place on the tubes that the tire liners sat moved often, which might have prevent "rub flats" as well.