COMPLETELY safe, using the same safe wash methods of top to bottom and not letting water dry on the surface, or in the sun.
It's a good suggestion to aid in the removal of additives and gunk on the surface, which is why they suggest doing it.
All the dish shop will ever really do is strip the wax/sealant coat, at least partially, so just don't continue to do it as a weekly regime and you'll be fine.