I can recall an old guy from up Northern WA telling me about 20 years ago, how he and a brother were fascinated with the local road building crews operations, moving bulk dirt for a new highway deviation.
This was the early to mid '1960's and they were teenagers with farm boy driving skills, and they knew how to operate machinery.
So, as all underworked young guys are keen, and this guy and his brother even keener - they thought they'd help the road crew out, and have some fun as well.
As soon as the crews were gone at knockoff, they'd jump on the machines and move some more dirt!
They apparently did quite a few hours work with the machines each evening, and I seem to recall he said it took the boss some time to work out, what was actually going on!!
I guess you would scratch you head a bit when the tractors were still warm next morning and the site looked different to last night when you knocked off!