I have worked on construction sites, and this strikes me as the classic "eyeballer" effect. That is, the type of guy who's been inappropriately using equipment for years but nothing ever happened, and he always just downplays people's valid concerns with "naah, been doin' it fer years! Trust me, it'll hold".
I've seen one occasion myself where they used a crane for lifting a cast-iron generator, but the generator was far heavier than what the crane was rated for. We heard this huge THUNK!, looked what happened, and saw this big-ass generator planted a good 30cm into solid concrete ground, and the crane at a 90-degree angle halfway up the boom.