For what must be the dozenth time, I've just accidentally deleted a large
tree by typing C-k while in a headline.

This is really easy to do because emacs users have "C-k deletes to the end
of the line" worn deeply into their neural pathways -- it's so automatic for
me that the keystroke is close to subconscious.  A mistaken C-k is
especially hard to detect because org-mode displays the result exactly like
what your subconscious expects, that is, a collapsed headline is deleted to
the end -- and the tree underneath is wiped out with no noticeable warning.

Feature request: add an option preventing tree deletion with C-k without
user confirmation.  Actually, I'd like an option to prevent it period.

If this option is already in there, then you're encouraged to tell me to
RTFM.  But then also please tell me where it is, because I can't find it.

Thanks much,

Scott