One of the ways manufacturers coerce users not to modify or even open hardware they’ve purchased is through warranty-void-if-removed stickers. These stickers are common on electronics equipment — Microsoft uses them on the Xbox One, Sony has them on the PS4, and you’ve probably owned a phone that had at least one somewhere.

These stickers are almost certainly illegal, as Motherboard points out in relation to the new Xbox One S. The problem with the stickers is that they run afoul of the FCC’s rules on tying repair services to specific products. This issue is also probably why Apple agreed to change its practices regarding iPhones, when devices that had been repaired by third-party shops would then suddenly fail when upgraded to Apple’s latest operating system.

“The stickers could be deceptive by implying consumers can’t use parts the warrantor doesn’t pre-approve, which violates the anti-tying provisions of MMWA,” FTC spokesperson Frank Dorman told Vice.

Companies don’t like to talk about these policies, most likely because they don’t want to admit they’ve been doing something illegal for decades. Laws like the 1975 Magnuson–Moss Warranty Act were passed to prevent companies from tying customers to expensive repair contracts, or requiring customers to use only approved hardware installed by “authorized” resellers. The common example for this is with cars, where it’s illegal for a manufacturer to try and force you to only install their own parts.

There are, of course, limits to these laws. If you destroy your transmission or engine while servicing them, the manufacturer is under no obligation to repair the vehicle. What manufacturers aren’t allowed to do is refuse to honor a warranty on your engine just because you installed a different set of speakers or an aftermarket radio. The obligation is on the manufacturer to demonstrate that your third-party repairs or modifications caused the failure, not the other way around.

Modern electronics are tightly integrated, but the concept is the same. Microsoft isn’t allowed to prevent you from opening your own hardware, and neither is any other manufacturer. So why do they?

The answer is simple: Because they know you won’t do anything about it. It’s a nifty example of how companies get away with doing illegal things — the cost of taking them to court and forcing them to comply with the law is higher than the value of the product. A car is expensive enough to repair that companies can’t get away with telling you to pony up thousands of dollars for their own parts and repair shops. On the other hand, a smartphone can cost $500 to $700, but that doesn’t begin to cover the cost of a lawyer to litigate the issue, and Apple, Microsoft, and other companies know it.

In Microsoft’s case, its warranty states that it ceases to apply if the Xbox One is “opened, modified, or tampered with.” It’s flatly illegal. But until someone brings a case against the company and litigates it out, electronics companies will continue to put these stickers on their products, and consumers will continue to believe the manufacturers are legally allowed to do.

The situation is also playing out in new ways thanks to the advent of DRM. Tractor manufacturer John Deere and the Library of Congress have both resisted any attempt to require manufacturers to share data on firmware or other DRM’d blocks of information, because it could conceivably allow for piracy or alter the function of the vehicle. John Deere has gone so far as to claim that by purchasing a tractor, farmers gain “an implied license for the life of the vehicle to operate the vehicle.” It’s the concept of software licensing, except applied to hardware, and the fact that it’s illegal doesn’t seem to concern anyone much.