No need for probable cause or reasonable suspicion at the border. If in doubt, travel naked and with a burner phone. Move data across borders using a PIE (pre internet encryption) service and never share your keys.
For Android there’s an app called AppLock that let’s you lock down every function of the phone to require a combination.
You can give an agent the wrong combo and it makes it look like the protected app has crashed instead of warning that the combo is wrong.
Burner phone, burner tablet and burner email. That is how friends of mine do it when they travel to Europe.