I would say that most of the time people don't even know that not everything written in a contract might be valid in case of a legal dispute. However, once in a while we have nice things, such as requesting to be refunded the windows license https://sistemainoperativo.it/#:~:text=Come%20chiedere%20il%...).
Unfortunately it's in Italian, basically if you don't accept windows (and office) tos you can be refunded, almost nobody knows this except some Linux users. However, if you follow the steps (such as not accepting the tos) you're basically guaranteed a refund or to win the legal dispute
I did that once, almost 20 years ago. Bought an IBM laptop that came with windows (there weren't any options w/o Windows back then, for consumers at least). I always planned to put Linux on it.
Rejected the TOC. Made a meticulous image report that showed careful unboxing and setup.
There was a line in the TOC that (from very vague memory) disallowed using the OS for a.o. nuclear power mgmt. I did work in energy back then (but mostly webdev), so I could not rule this useage out. Send it along to Redmond and got a prompt reply from som e salesman for some kind of "industrial licence" for insane amounts. A few back and forths later, I got a measly €20 Euro's back. They put the rest down to admin fees, and OEM discounts.
Anyway. It ran SUSE and (k)ubuntu perfectly.
I guess it's much easier nowadays. But I buy my laptops preinstalled nowadays. Open the lid, answer five or six questions, restore my backups (/etc, .files, ~), reinstall the packages from packages.txt, reboot and continue working.
As of today, in Italy, you get refunded the average market price for a license and not the oem price (roughly ~20€),so depending on the windows version you get 40/80€ + if you have office, you get a few other bucks back, upto ~115€ for windows + office. And yeah, it's a bit easier today but companies still try to make it difficult on purpose, such as asking you to ship back the product, while you're not obliged to. I spent last hour reading the legal proceedings on the site I posted and lol, they're kinda all the same, you ask a refund, you get told to ship it back, you do the "messa in mora" (you legally tell the company to refund you), they tell you to ship, you say you're not obliged to, you're eventually refuned
Just to add: This right to be reimbursed of Windows OEM has taken extremely long in the 1990ies to become a right, after much lobbying from Linux fans.
Unfortunately it's in Italian, basically if you don't accept windows (and office) tos you can be refunded, almost nobody knows this except some Linux users. However, if you follow the steps (such as not accepting the tos) you're basically guaranteed a refund or to win the legal dispute