[LakewoodM32Fan]

People should start with a basic understanding that your guitar's finish (primarily your nice guitars) are generally not "fully cured" in some cases for many years. It's just the nature of it, and the amount that they put on, buff, shine etc. to provide as much protection and shine as they can in as minimal a layer as possible to keep it resonant.

And pretty much everything reacts with everything to some degree, just the laws of nature/chemistry. Even something that is "inert" at the time is still exposed to the air/humidity/dirt/grime in your house and those can settle on the "inert" contact points and, if your guitar is kept on there and not moved for long periods, can have an effect.

Now to minimize the possibility, simply storing your guitar every few days/weeks (and wiping it down, at minimum on the contact points) will mitigate any issues. But leaving something in contact with something else for weeks on end, especially if your home environment isn't the most friendly to guitars (i.e. humidity and temp could go above recommended specs, again the airborne dust/grime you can't see but somehow accumulates over time on your flat surfaces and blinds)...yeah all that stuff plays a part slowly, over time.

On something like the Hercules stand, where the main contact points are on either side of where the headstock meets the neck, which are traditionally not gloss and have dark woods, you could possibly leave it there for months on end and whatever happens may not be easily visible to the naked eye. However as I mentioned there was a less than 2 year old Martin with a light colored maple neck/headstock at Guitar Center where there was clear yellowing from the contact with the wall hanger they use there. Continuing with the Hercules example, rather than cradle arms at the bottom, which would contact a lot of the tail-side part of your guitar, there is instead just to small contact points where your binding would touch pads. If you have dark binding, again you may never notice this. If you have ivoroid or light maple binding, you might.

And overall, it's a question of how much do you even care if there is slight discoloration over years? I never buy my guitars with the thought of resale, I buy them with the hope I'll enjoy them for years to come. That said I do try and take care of them to a moderate, but not OCD, degree. But I take care of most of my stuff of value in the same way, not just my guitars.