Comment 4 for bug 77853

Well, I'd say so.

The only collateral effect might be the early publication of the custom-part of the uploads on disk during mirroring process.
But, AFAICS, even if it is possible in the DB model, this practice isn't used currently, i.e, stored source uploads don't contain any custom part:

{{{
launchpad_prod=> SELECT drq.id from distroreleasequeue drq, distroreleasequeuesource drqs, distroreleasequeuecustom drqc where drq.id = drqs.distroreleasequeue AND drq.id = drqc.distroreleasequeue;
 id
----
(0 rows)
}}}

I think it will be safe to do If we enforce this condition with DB constraints and maybe also upload-policy parameters (source uploads must be "truly_source_only")