That large lever has a safety pin in it that will shear when there is a large force exerted on it, essentially if the car is on the jack stand it will take a crap load of force to lift the lever and the shear pin will break long before the lever is moved. Those torin pin style jack stands are also known to have issues where the load bearing surface will warp or completely break off. Plus the base is alot smaller than the traditional jack stand so those arent as stable.Something like this where the pin secures the height. The ratchet style depends on friction essentialy to stay in place and often has a large lever that could be kicked and knocked out.
This still has the risk of a pin breaking of course. That is why you don't bet your life on any of these alone. As Filippo suggested, always have a backup when using jack stands.
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There was a YouTube video testing it, in some cases the sheer pin did not break. But it took hundreds of pounds to lift so not likely to be kickable.All good points and even more reason not to trust any of them alone.
The R&T article explains in this case the support pawl can disengage under shifting loads - let alone the lever itself being hit.