I bought one and have been using it just fine. Just depends on who you buy it from (e.g. is the guy a student? a CEO? a homeless guy?). If you know their true identity then they'd have to be really stupid to have done something nasty to it and sold it to you... and if you know who they are, all you have to do is ask how they obtained it.
Note to self: NEVER assume privacy when using ANY phone with a camera or a mic.
Looks like you can't assume it when you're not using it either.
I'd go so far as to say, these days, to just NEVER assume privacy. With ANY tech. Ever. Doesn't matter where it's manufactured, nor where it's sold. Everything is data mined, one way or another. The "cloud" (really "someone else's machine") opposes privacy by definition. If the leak isn't in the hardware, it's in the software, and if not there it's in the pipe. There's no feasible way to control every point along the line.
I mean if you manufactured it yourself, I think you can be fairly certain that it isn't sending your stuff to the cloud.
Do you trust the tools you used to manufacture it?
Depends on the complexity of the tools.
> Note to self: Continue never buying used Android phones.