You wouldn't knowingly hand your cell phone over to a stranger so they can look at whatever they want on your phone, but when you plug your phone into a free charging portal at a hotel, airport or someone's laptop, you're kinda doing that. So, let’s take a look at ways to protect your info:
First: when you plug your phone in, it should send a notification asking if you trust the device. Hit "do not trust." You'll still get a charge, just without allowing access. Androids and iPhones have these alert systems.
Second: turning off your phone might help. But experts say the only way to be 100% safe is to use a wall plug, portable charger or just plug your phone into your laptop.
And you have another option if you're willing to spend a little. You can buy a data blocking adapter. It lets your phone charge and blocks out all the data-sharing capability. You can find one on Amazon for less than $10.