Another ...

...
? possibility I'd been "chewing" over - (

...
there I go again !) - is based on a
long-held theory [of
MINE ] that supermarket chains
MIGHT, from time to time, be given "first refusal" as it were, on batches of sub-standard and/or inferior goods (that manufacturers would otherwise find difficult to dispose of through the normal channels) and thereby, in turn, pass them on in bulk sale to
unsuspecting consumers.