Chris:
 
Thanks for your interesting response.  The bumblebee colonies I'm
familiar with are from about 9,500 feet elevation in the Colorado
Rocky Mountains (near the Rocky Mountain Biological Lab).  At
that elevation, a large colony might have 30 to maybe 40 workers
by the end of the season; many colonies never have more than 12-
20 workers.  A colony this size does not have a "tremendous
'warehousing potential'" for honey.  In colonies at this
elevation I have never seen sealed cocoons with honey, nor have I
ever seen more than a single honeypot made by a queen.  Thus,
there seem to be quite significant difference between the
colonies you have described, apparently from lower elevations,
and the ones I know from higher elevations (in an area where
Native Americans used to spend the summer).  I am still sceptical
that high-elevation bumblebee nests, which might have only a few
ml of dilute honey, would have been the object of searches by
many kids.  Thanks for pointing out these differences among
species of bumblebees.