Of course you did. You're not handing your device over to Best Buy, you're handing it over to Jimmy on the Geek Squad who is quiet and a bit weird. And he loves to snoop into other people's phones. Not for identity theft or reselling naughty pictures, but simply for the fun of snooping on other people.
Backup your device and wipe all of your data before handing a phone over to anyone else. It's just safer that way.