I have successfully done this in the past. In Arid/dry setups it will not work because yes they do need moisture. Without moisture they will die fairly fast. So Grammostolaspp., Brachypelma spp.(I'm talking hobby wise, I know some species are found in rainforests where it's rather moist), and other species with the same care requirements are out.
Adult Ts will leave them be unless they are seeking a little snack or something. If you really have a bad habit of leaving prey remains in your tanks, get some.