

When you enter the US, you have to claim your checked baggage as part of the process of going through customs, then re-check your bags if you’re continuing on a domestic flight.
If you have a device in your checked bag:
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you’re violating the safety rule about not having lithium batteries in checked luggage.
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if you’re asked if you are travelling with a phone and you lie and say you don’t have one, then if they search your bags and find it, then they’ll have strong evidence that you lied to a federal officer, which is a crime.
American Airlines will ask you to remove devices from your checked bags is you tell them that you have batteries in your checked bags. Airlines are allowed to have more strict rules than what the FAA allows.
https://www.aa.com/i18n/travel-info/baggage/restricted-items.jsp