For me, there were some questions about my technology, but not a lot. Mostly we agreed on terms, and then they came up with a 40 page contract :) (the bus-dev guy said they don't really treat a small acquisition like mine that much differently than a larger acquisition in terms of contract verbiage). I had my lawyers (no I did not have any before this offer), review it.
But overall I felt that someone, who later I'm pretty sure turned out to be the CEO, had told their Business Development guy, just acquire this thing (and bring him along if you can), so they just went about doing that and it came out ok.
Maybe being contacted by a product manager or engineer should make you cautious.