This is a HBR cure.
First, for those of you not following the official draft closely, as
of a recent commit, I have audaciously and iconoclastically added this
sentence to the (now single) section on object code disribution:
Each recipient of the Covered Work from You is an intended
third-party beneficiary of this License solely as to this section 
with the right to enforce its terms.
If any of the lawyers on this list have any comments of a strictly
insider-professional-knowledge *legal* nature on this sentence,
including arguments for its deletion or modification, feel free to
speak up (in a HBR-compliant manner of course).
If anyone (non-lawyer or otherwise) thinks it would be bad *policy* to
live in a world where a GPL-like license could be enforced through the
legal system by the obvious immediate beneficiaries of the source code
requirement, feel free to speak up (in a HBR-compliant manner of
That said, on to the HBR cure: I had a conversation with Bradley Kuhn
in which we very briefly discussed this issue, as Bradley was long
under the impression that the GPL could not *possibly* support an
argument that mere licensees have some standing to enforce the source
code requirement (despite the fact, of which Bradley might not be
aware, that over the years some legal academics have at last taken the
question seriously, if skeptically, and some private practice lawyers
[admittedly seeking to profit from the erstwhile open source boom, the
SCO crisis, etc.] purported to take this qite seriously too).
I noted the obvious point that copyleft-next and GPLv2/GPLv3 are not
worded identically, so his comment was partially irrelevant.
Bradley mentioned some interesting work that Australian lawyer Brendan
Scott had done attempting, AIUI, to use Australian consumer protection
law to give a basis for GPL licensees to sue upstream distributors for
failure to provide source code. It is not clear whether such efforts
have been successful.