We have water fountains and soda vending machines at work but with the heat
right now I am sweating it out faster than I am drinking it.  At least I
will be on vacation next week so I will be getting a break.

Here the thing you have to remember about Blood Glucose and the water
content of your Blood.  When you are HYdrated properly your BG
readings are considered accurate.  Ie a BG of 105 is an actual 105.

However as we DEhydrate (the water content of our blood is decreased)
everything that is in our blood because "concentrated".

So we have to determine WHY we are becoming dehydrated.  In the case
of HI BGs due to over eating or a lack of insulin which also leads to
DKA.  The HI BG will trigger the dehydration as the body attempts to
flush excess glucose through the kidneys.  As this continues into DKA
for type 1s, the rate of dehydration and the rate at which the BG
climbs increases and worsens the rate of dehydration.

Now in the case "Davybear" describes he is working in an extreme
environment.  The stress from the heat alone, even without physical
activity would lower ones BG.  Add physical activity to that and the
risk of hypos increases.

Now as he is going hypo he is ALSO dehydrating(because of his extreme
working environment).  2 separate events taking place at the same
time.  As he starts to experience hypo symptoms the water content of
his blood is dropping, and the Glucose still in his blood is becoming
more concentrated.  So when he tests his BG he now gets a FALSE
reading of 105.  But with the lower amount of BG in the system because
of the hypo and the lower fluid level in the blood stream because of
the dehydration his body is still not going to be getting enough
glucose throughout his body to prevent the effects of the hypo.  He
needs both fluid replacement and glucose to treat this situation
correctly.

When I worked as a welder I experienced this several times.  I had to
test my BG several times at work.  Not a problem where I was in a
shipyard.  I had to keep water AND juice or regular sodas on hand at
all times.  Liquid sugar metabolizes faster than glucose tabs or candy
or table sugar.  Drink the water on a regular basis, even if you are
not all that  thirsty.  You can also find sugar free sport drinks now.
Review them with your doctor.  Their cheaper and sometimes easier to
get than the electrolyte replacement drinks.

Consider this based on my experience only, but I suggest you talk it
over with your doc.  In your work environment if you feel any hypo
symptoms and you do not have the ability to stop what you are doing
long enough to test your BG and hydrate and treat the hypo.  then err
on the side of caution and simply act as if you are hypo and at the
very least treat for a mild to moderate hypo.  Far better to end up a
little hi, than dead because you had a hypo and an accident as a
result of it.

"It's never happened before".  "It can't happen to me". are all
natural foolish responses but they do lead to the Darwin Effect.