I stand corrected. There are locals that harm ecosystems so my comment should have included them too.
On to citizenship. Without documentation there is no proof that you are indeed a citizen. You can be detained without cause if you are deemed a terrorist. Patriot Act was passed for that reason... stripping you of rights to have a reasonable cause and a warrant to get arrested. Buuut... even without that you can be detained without having paperwork and even deported somewhere. That, of course, is an extreme scenario but having documentation on you definitely keeps you out of trouble.
When I had my green card I was REQUIRED to have it on me at all times... mind that I am white caucasian who speaks english fluently barely with an accent. When I got my citizenship, I made a point of never leaving my house without documentation just in case.
On to citizenship. Without documentation there is no proof that you are indeed a citizen. You can be detained without cause if you are deemed a terrorist. Patriot Act was passed for that reason... stripping you of rights to have a reasonable cause and a warrant to get arrested. Buuut... even without that you can be detained without having paperwork and even deported somewhere. That, of course, is an extreme scenario but having documentation on you definitely keeps you out of trouble.
When I had my green card I was REQUIRED to have it on me at all times... mind that I am white caucasian who speaks english fluently barely with an accent. When I got my citizenship, I made a point of never leaving my house without documentation just in case.