You have "trust issues"? About what, your name being in S&W's database?
OK, you're not going to like this, but it's the truth:
It's 2015.
You are an American adult, and you filled out a 4473.
You're in databases for the ATF, FBI, NSA, CIA, DHS.
This is not tin-foil hat paranoia, it's the current reality. There is nothing you can do about it. Accept this and move on, or you're going to give yourself an ulcer worrying about it.
The sky is blue, water is wet, and this is America now. Whether we like it or not isn't going to change anything.
That being said, the other posters are correct, filling out the warranty card is not a requirement for warranty service from S&W.