Any Kurd who enters Turkey, airport security ask for the passcode of his/her phone in order to check if there's any stuff related to Kurdish political organizations

It's still blowing my mind when I think there are still thousands of Kurds, daily, go to Turkey for tourism. They ask for passcode, and steal it for a while, then check it and if they find anything, they insult the person and don't let him enter Turkey.

I wonder if they can install any surveillance app in the phones? How someone clean his phone after coming back from there?

airport order organizations passcode phone political privacy security turkey