That said, most liars are really really bad at lying. "We care about your privacy! Now let us load 1000 tracking libraries, kthxbai" is pretty easy to spot.
I think the scarier case is when dealing with a government adversary. They're simply not as stupid, and you never know when it could happen: https://archive.ph/rI8mE
For those cases, I get unnerved when things seem too good to be true. If I didn't know former Mullvad employee(s), I'd be deeply concerned about them, too.