I'm a Mexican citizen living in the US working as a Computer Systems Analyst. Been here for 1 and a half year and my wife and daughter joined me a year ago. I just recently moved jobs and the UCSIS approved me a work permit and I-94 until 2019. I came here as a TN visa, and I am worried if asking for a green card would get me and my family in trouble.
OTOH, I don't think they actively seek you out to revoke your TN status, but it would make border crossings pretty much a non-starter.
All this is remembered from when I was on a TN status from Canada ~5 years ago.