We all know how governments work. If you want to lose your U.S. citizenship, NOTHING you do will avail to assist your purpose. If you want to maintain your U.S. citizenship, you can almost be guaranteed that mistakes made at the border will come back to bite you, and invariably at the most excruciatingly inconvenient moment.
But let's be perfectly clear. A U.S. citizen is required, by law, to enter and exit the U.S.A. on a U.S. travel document -- period, end of story.
The following actions do not automatically have dire consequences, but <i>could</i> be used by the U.S. Department of State to revoke citizenship from multinationals, without notice (you will discover it when you try to renew your passport or cross a border into the U.S.A.):
- Entering the U.S.A. on a foreign travel document
- Getting a U.S. visa of any kind (this is particularly dangerous, as a U.S. citizen would NEVER do this!)
- Presenting a foreign passport to a U.S. peace officer (except when specifically requested to do so)
- Not including American citizenship on forms that ask you to declare your citizenship (even when abroad)
- Failing to file tax returns
- Making statements (on blogs, to friends, in writing, in private, etc.) that can be construed to mean you committed an expatriating act with the intent to relinquish U.S. citizenship
- Making public statements and/or taking public actions that the U.S. Department of State considers inconsistent with an intent to maintain U.S. citizenship
Again, these actions do not guarantee a loss of U.S. citizenship, and are unlikely to result in loss of citizenship. But should CBP and/or the State Dept. decide to turn their beady eyes your way, committing these acts (especially applying for a U.S. visa) could result, in a worse case scenario, with a loss of U.S. citizenship and a permanent bar from re-entry into the U.S.A.
Contrariwise, if you want to relinquish U.S. citizenship, a great way to do that is to become a Canadian citizen; return your passport, by mail, to your nearest consulate, with a letter stating that you are no longer a U.S. citizen, including proof of Canadian citizenship; filing a "final" U.S. tax return; and applying for a U.S. visa with your Canadian passport. There's no guarantee that the U.S. Government will immediately honour these acts, but they certainly create a very legal paper trail of your intent to relinquish U.S. citizenship when you committed an expatriating act (i.e., becoming a Canadian citizen) -- and U.S. courts like clearly documented paper trails.