The US is hardly the only country where this is the case and locking down your phone is almost entirely pointless (see xkcd #538).
If you're concerned about having it searched, don't bring your primary phone. Go to a phone shop, buy an old phone, put your SIM card in it, and use that instead.
If you're concerned about having it searched, don't bring your primary phone. Go to a phone shop, buy an old phone, put your SIM card in it, and use that instead.