Again, Go deflate your tires to 25-26 psi and tell me you can’t notice the difference, let along a guy who’s sold tires for a decade or more not being able to notice immediately a 20-30% psi deficiency. The claim is flat out laughable.
By kicking it or hitting it with a stick? Generally.
By visually noting the effects of it trying to hold up a quarter ton or more? Probably.
By trying to compress it with one hand? Probably not.