In article .com,
wrote:
I suppose I could call the local news broadcasters of this region to
come and take a picture and include it in their news tonight or
thereafter of a case where a crabapple is in bloom and flower and this
is 16 October. Because few are going to believe my words on the
Internet.

Probably all the Hopa crabs in your area are doing the same thing.
Hopa is a very popular hardy ornamental crab for cold climates, so
there are probably lots of them around.

Or, someone else, somewhere else has the same observation or experience
where a tree is in bloom and flowering at this moment in time. I
suppose plants in greenhouses can be tricked into blooming out of
season. We had a cold snap a few weeks ago and now are above normal
temperature which may have tricked the crabapple into blooming.

Spring-flowering woody plants being "tricked" into blooming in fall, due
to unusual weather patterns isn't all that rare. In some areas it happens
every few years for some cultivars. It certainly isn't a desirable trait,
so most people would regard such cultivars as unsuited to that area if it
happens very often.

Would anyone have a metabolism explanation for this crabapple activity
to bloom before winter? Are apples species easily tricked?

Apples and other spring flowering temperate climate plants have a
chilling requirement. They have to be exposed to a certain number of
hours at a certain temperature range in order to bloom. I don't recall
the exact range, and it probably differs for different species, but it's
more or less domestic refrigerator temperatures in most cases. (i.e. on
the order of 40-45F). Normally, plants accumulate these hours (actually
some kind of product of temperature and hours) in both fall and spring.

Chilling requirement is genetic and has been selected for in some apple
cultivars to enable them to be grown in warm climates. Note that low
chilling requirements are suited both to warmer climates, and to cold
continental climates, where there isn't a lot of time at these temperatures
in spring and fall. Hopa was developed, IIRC, for the Canadian prairies,
so it may be a relatively low chill cultivar, i.e. easily fooled by an
unusually warm fall.

I don't know the mechanism of chilling requirement, but since it's a
feature of such extremely unrelated plants as tulips and apples, I
wouldn't be surprised if there are several different mechanisms. Since
it's an important factor in breeding apples for warm climates, there's
probably a fair bit of research done on it. IIRC, Israel is the source
of most of the low-chill apple cultivars grown in warm climates these
days, so that's probably where a lot of research has been done.