For entering the US you want to fully wipe your phone first. Lockdown mode is useless since they will just hold you in a basement until you unlock the phone for them to clone.

> Lockdown mode is useless since they will just hold you in a basement until you unlock the phone for them to clone

If this is a risk for you, sure. Wipe it. For most people they may ask to fiddle around with it before giving it back.