“We’d been talking about how dangerous these charging stations could be. Most smartphones are configured to just connect and dump off data,” Markus said. “Anyone who had an inclination to could put a system inside of one of these kiosks that when someone connects their phone can suck down all of the photos and data, or write malware to the device.”
Brian Krebs outlines the security risk of using cellphone recharging kiosks. Smartphones have so much data on them, much of it personal. If you have to use a charging kiosk, powering it off first may be the safest route.
This is yet another reason that I consider battery life such an important factor in a smartphone.