Removing \M-s binding

In wl-folder-mode-map, \M-s is bound to wl-save.  However, this conflicts
with Emacs's binding for search-map; e.g., \M-s o is bound to occur.

Since wl-save is already bound to \C-x \C-s, I wonder if the \M-s binding
could simply be removed in WL.  (Just a matter of deleting line 212 in
wl-folder.el.)

(If that's not desirable for some reason, how can I remove the binding in
wl-folder-mode-map in a way that maintains the search-map binding?  I
suppose I can't just set it to nil.  I tried with local-unset-key, but it
didn't work.)

Relatedly, \M-s is bound to wl-summary-stick (a very useful command) in
wl-summary-mode-map.  If WL's bindings should not override Emacs's general
bindings (and I think they shouldn't), perhaps that binding should be
changed too.

I'm on wanderlust-20190623.1332 from Melpa.

All the best,
Greg