Accessibility is not only about opening a case, but accessing things that require maintenance, like coolers.
It seems unreasonable to me that manufacturers prevent users from even cleaning their devices without voiding warranty.
On top of that, stickers are a lazy answer to the problem of damaging an equipment because of the so called unqualified tempering. An appropriate answer to that in my opinion would be to make parts cheap and available so that users can go to a third party workshop to have their systems cleaned, checked and repaired, so they don't have to do it themselves. This is why right to repair is also important.
My comment's context was the response to AussieWog93 original comment. I think his point is that unqualified tampering with the internals probably should void the warranty. A user is qualified to clean the cooler, and do other basic maintenance.
A good example is when someone follows YouTube videos to mod their xbox with 1/4 inch wood burning tool rather than a soldering iron.
I think this misses the point that the problem is the unqualified tampering with the internals, not removing the case so you can access them.