Yeah, "letter of the law" defenses tend to work better when the intent of the rule in dispute is unclear. There's lots of arguments about the intent behind the 2nd amendment, which means it mostly falls back to a "letter of the law" interpretation. There's no dispute that the NSL obfuscation compromise is intended to obscure the number of NSLs. Revealing the number of NSLs, while still following the "letter of the law," wouldn't fly in front of a judge.