Please put me in the camp of "never say never".
If a site (usually boondocking) might require some
blocking ..use it. I always chock the tires. Same
goes with asphalt camping out here in the desert
in July.
A caveat for those still under warranty... regardless
of what you read on these forums , do what your
RV manual indicates as the proper technique. A quick
scan thru various manuals on the net indicates differing
manufacturer recommendations . Failure to comply
wouldn't leave you a leg to stand on !
(see what I did there ?)...ha !
Charles