Do Safari private tabs stay open after iPhone shutdown? Does Private Browsing in Safari keep private tabs open when you restart your iPhone 6, or do they get closed automatically?

If private tabs remain open, when opening Safari will you see the normal tabs or the private tabs?
I just checked this on my iPhone 6 running iOS 10.3.3. I opened a private browsing tab and went to a site then powered my iPhone off. 

When it restarted I opened Safari again. My private browsing tab opened up to the exact site I was on when I powered off. 

So I think you're busted on this one. But you've learned a valuable lesson about private browsing and always having a passcode on your device :-).