I believe that you need written permission to cross state lines.
I live on the in PA, on the WV border.
Do I need written permission, every time, from my betters, to go hunt coyotes on my buddy's farm, in WV?
Do I give up any 4th Amd protections?
Suppressors do not need paperwork to cross state lines. All other NFA items do. There is a small loophole for short barrel rifles. You can remove the short barrel and replace it with a 16” barrel and cross state lines. You are not allowed to bring the short barrel with you.
According to the internet, unlike all of the other items regulated by the NFA, suppressors do not require that you fill out DOJ form 5320.20 as long as you are traveling to a state where they are not prohibited (California, Delaware, Hawaii, Illinois, Massachusetts, New Jersey, New York, Rhode Island, and the District of Columbia).
But i’m not a lawyer, and don’t play one on the internet, so check with competent counsel before sending any coyotes to their eternal reward.
And yes, this is a violation of our God-given constitutional rights, imho.
No. None. That is a myth the people who are too stingy to buy one for themselves made up to discourage you from having one either.
Supressors are the only NFA item that you don’t need an approved form 5320.20 for.
Not that I see anywhere. Suppressors are treated differently than SBRs, SBSs, or full auto firearms.
Do I give up any 4th Amd protections?
The ATF has the legal authority to demand to see your tax stamp (also serves as registration document). Suppressors are considered NFA "firearms" as a legal definition.
They don't have the right to see your suppressor, at least as far as I can tell.
It seems highly unlikely they would ask to see the tax stamp if you do not have the suppressor in your possession.