The max cold pressure rating does take into account the increase in pressure from a tire heating up.
Bike manufacturers sometimes use tire pressure "recommendations" to assist with softening the suspension.
Of course, (except for Ford/Firestone and the Explorer fiasco) they've done their research and should be well within safety margins.
Tire life and handling is a different story though.
If your PSI is at the mfgs recommendation, the max cold rating OR somewhere in between; while the tires are at ambient temps (cold).
There is no reason to check pressure when hot.
If there is a big swing in ambient temps; it's a good idea to verify cold pressure though.
We have TPMS (tire pressure management systems). We aren't taking IR guns out to check the tire temps, but it is good information to know. Once you have found the sweet spot for pressure for your particular bike, load and riding style, it shouldn't change much except for, like you say, adjustments for ambient temp swings.
Maybe it is a bit of overkill for folks without TPMSs to check the tires multiple times every day, but having a TPMS can save you from being stranded in the middle of nowhere with a flat tire. I would much rather be able to find a shady or dry spot to fix a tire than on the open highway in the summer sun or in a rain storm.
Yes, the max recommended tire pressures do take temperatures into account. At that pressure, the tire should not flex much at all so there should not be much as much temperature rise, so they don't expect any failures. More cold pressure and they can blame you for the tire failure. Less than bike mfg recommended pressure, they can blame you.
In between the two, statistically, they are safe, so it is extremely hard to prove mfg defects unless a Ford/Firestone situation exists. And, like you say, they don't warranty tread life or performance on motorcycle tires. Most motorcycle tire mfgs apparently don't put much research into what pressures their tires run best for particular applications. They probably take a few of the most common bikes that the tire fits and do all of their development from there. Just like for auto tires, they expect the vehicle mfg to do the fine tuning for their specific vehicles. However motorcycle tires are far more variable than auto tires, so tuning for one tire does not mean much if you get away from that brand. Unfortunately, Kawi when with the crappy Bridgestones, so we have to do our own fine tuning.