If travelling I'd highly recommend some simple practical changes to the iPhone (and assume android similar) whereby you can't access the top pull down menu unless the phone is unlocked.
This prevents gaining access to turn off data/enable airplane mode etc, and if the manual side button is used to power down the phone it actively states that location services will keep the phone trackable even when switched off.
You can also prevent notifications (eg 2FA txts) from being displayed in full on the front screen when locked too.

That and a wrist strap that fixes into the phone case gives some additional physical protection if heading to known theft hotspots like London etc