Aww yes-
It is an oversimplified statement that does not take into account a few
corner cases. This includes at least some devices with firmware such as the
AR9170 chipset. However the statement still should generally hold true. More
so for the libre-kernel distributions than the mainline kernel.
The problem with Virtual Box is the program's code is not up standards for
inclusion in the mainline kernel. Linus has attacked it before if my memory
serves me right. As a result you may run into problems.
If anybody else's memory is better than mine on this issue feel free to
correct me.