Big time hater here. lol.
Legal requirement? I'm not really sure. I've only read on here that it's a good idea to have a copy of the letter in the unfortunate case where I might want to, or have to, offer proof of the legitimacy of my paperweight and it's prior acceptance by ATF as being indeed a paperweight.
More sadness- The San Jose build thread along with the DS Tactical thread has gone poof. Thats where I was reading a lot of what, seemed to me, good info.
The very last thing that I want to do is give the powers-that-be an opportunity to pick low hanging fruit.
Yea, yea I know. Burden of proof and all of that. I keep it right along side my copy of the 2nd A.