RFC7208 upper case macro expansion ambiguity

RFC7208 describes upper case macro expansion as follows:

   Uppercase macros expand exactly as their lowercase equivalents, and
   are then URL escaped.  URL escaping MUST be performed for characters
   not in the "unreserved" set, which is defined in [RFC3986].

RFC3986 tells us that:

   unreserved  = ALPHA / DIGIT / "-" / "." / "_" / "~"

The question is, may an implementation URL escape chars that *are* in
the unreserved set?  For instance, if localpart is "~ralf",
is an %{L} expansion of "%7Eralf" acceptable?  Or should the
test suite mandate an expansion of "~ralf"?  What about silly
choices like expanding ALPHA chars?

-- 
 	      Stuart D. Gathman <[email protected]>
"Confutatis maledictis, flamis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.