To sum it up, what Jimlin posted is what some of us know, either through knowledge or practical experience. The catch being, if you don’t have either, you may not recognize what these “real world” limits are, or if you’re inadvertently doing something inherently unsafe.
To that end, Mfgs put their conservative ratings on the vehicles to 1. Reduce warranty claims. 2. Boost perceived reliability. And 3. Minimize liability.
If a person chooses not to understand or is not inclined to understand, the mfgs rating stickers are the very safe, conservative default limit.