"the Legal issue is something we all would love to know"
Then some folks planning to visit BC, Canada might be interested in this -
if not, no need to read further.
from the BC Motor Vehicle Act Regulations:
Overload prohibition
19.11 (1) Unless operating under the provisions of an overload permit issued under the Commercial Transport Act, no person shall operate or cause to be operated a vehicle that is loaded in such a manner that the gross weight carried by any axle exceeds the gross weight rating for that axle as specified by the vehicle manufacturer, or the gross vehicle weight exceeds the gross vehicle weight rating for that vehicle as specified by the vehicle manufacturer.
- but -
does not apply to a vehicle
(a) manufactured before January 1, 2001, and
(b having a gross vehicle weight rating of 5 500 kg or less.
(more on this exclusion in second link below)
btw the BC Commercial Transport Act defines commercial vehicle as:
"commercial vehicle" includes
(a) a motor vehicle having permanently attached to it a truck or delivery body,
<snip>
In my and others experience, pick ups are registered in BC as "Commercial" even though they may be licensed and insured for private use only.
More info found here:
http://www.drivesmartbc.ca/miscellaneous/topic/alphabet-soup-gvw-gcwr-gawr-and-more#comment-597
note from that link above, the following :
If you are from outside B.C. your pickup truck is considered to be covered by the Commericial (sic) Transport Act regardless of the fact that you use it only for pleasure and it is not registered to a business or for business use.
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Also I believe a driver in BC can be given a ticket for an unsafe vehicle at a POs discretion using visual clues (Violations Act section 37.35 Operate unsafe vehicle). See link for more (I think this may have been posted on this forum before - my apologies forgetting that poster):
http://www.cvse.ca/references_publications/pdf/MV3231(082003)GVWR.pdf
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fwiw I have also read (didn't keep the citation) that to counter a PO or "credible person"s belief in a weight (with respect to a believed overload) it is the drivers responsibility to prove the weight is otherwise.
Again fwiw, also read on a CVSE (Commercial Vehicle Safety Enforcement) site the following:
We weigh vehicles post collision for police collision reconstructionists so they can use momentum equations for speed determination. Or private vehicle owners with trailers or loads if they have a concern.
From link:
https://www.tranbc.ca/2012/04/10/weighing-in-with-the-cvse-no-such-thing-as-a-silly-question/
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DISCLAIMER: I am not a LOE, or in the "Legal Industry". The above are just a few things I found online that apply to my jurisdiction ...