It does not reformat and reading "how to hack your NAS" and "Linux for newbies" (you get my drift) puts the fear of God in me that I will end up with a nice white brick
The problem with the reset button or command line reset is it probably just runs some script..... if they've installed something then the script won't trash it.
Anyhow.... I understand your point of view, so I'll leave it as "your call".