Also when manufacturers go for cheap and use some fly-by-night components for things like networking cards and the like since most users are Windows users and won't notice the missing Linux support.
By the time anyone realizes, that little fly-by-night company changes its name to some new company and keeps on lying.
This is a problem with ODB II adapters and readers and with USB sticks, too.
For example, cheap USB sticks are often programmed to lie and claim that they are a larger capacity than they can physically hold.