I would keep that consistency as well for land hermits, as long as there is a separate saltwater pool/dish handy at all times when they need to fill up the molt sac.
Oh, and here is a bit more information about land (non-hermit) crabs, the blue Florida Cardisoma sp. crab, that can also be applied to fiddlers when making their habitats at your personal place (with the fiddler habitat much more "shoreline"-type):
Adults utilize a range of habitats and tolerate a wide range of salinities. Blue land crabs are limited to areas where they can burrow to intersect the water table and maintain a 1-2 liter pool in the bottom of the burrow. Thus they are functionally limited to areas where the water table is within approximately 7 feet of the surface. Competition for optimum shoreline burrows may be the force that drives terrestrial crabs to migrate to inland areas.
Hopefully the information from this website is up-to-date...