It's worked for me.

My beloved old beater bike, with 26 x 1.9 tires, kept getting punctures in the same place. I tried everything that I could think of but I never did find the offending thorn or needle of glass that was causing the punctures. I cut the valve stem out of an old inner tube and used it between the tire and inner tube and commuted to work that way for about 6 months. I had no flats during that period.

I've never tried it with a skinny road bike tire, I'm thinking that might be a lot to stuff in there, but who knows?