There is some disagreement on this, but on paper it would seem that quick release is strong enough, if used properly. After all, early mountain bikes had horizontal dropouts and quick release mechanisms. The torque generated by granny gear far exceeds even the strongest rider's torque on a traditional fixed/singlepeed drivetrain(posited by the Sheldon). Those bikes didn't generally have problems with the wheel being pulled forward in the dropout, IIRC.