never lost a gas cap or forgot to put one on, that's first thing i do after i'm done filling up. my walk behind didn't have a tether and it never was lost, my scag tiger cub had dual tanks and i never lost a cap or any gas from forgetting to put them on, and my cheetah has tethers on both gas caps so i doubt i'll ever lose a gas cap on that or forget to put the cap on...
fully lic. and ins. 10yrs exp.