> You invoked standards. What do the standards have to say about the
> behavour of `tar --unlink'?  Hmmm?

"Hide under the desk and whimper."

> Personally, I think it would be nice to fix tar so --unlink allowed
> the old-style flags. Can we do that?

"Can", certainly.  It's only software.  But "should"?  I think I can only
see confusion from any attempt to combine -- flags and traditional tar
bundled flags;

> Or are we headed for a standards-weenie-vs-good-engineering argument?

and if confusion would result, standards and good engineering agree (as they
do more than one who reads standards might suspect ;-) ).

I think, though, that a "U" bundleable abbreviation is a good solution
that both solves the problem without (further) confusion and fails to
irritate standards any further.  (It's unfortunate that "B" is already
taken. else I'd agitate for making it the abbreviation for
--block-compress.  Perhaps, as a Really Gross Hack, --block-compress
could be assumed if the output filename starts with "/dev/"?)