Juice jacking is ability for cybercriminals to replace legitimate, public USB chargers with devices that have the capability to download data from your phones. Just this month, the Los Angeles District Attorney’s Office warned travelers of the potential dangers of using USB charging ports in public places.

However, when asked, the DA’s office said they have had no official reports of Juice-jacking taking place in the area. In short, many believe this cyberattack is feasible, but not widespread.
My advice is to use either power packs or plug into an electrical outlet if at all possible. Even though this isn’t widespread to date, caution should still be exercised.
For more information, see Snopes at https://www.snopes.com/fact-check/juice-jacking-real-security-issue/ or How to Geek at: https://www.howtogeek.com/166497/htg-explains-what-is-juice-jacking-and-how-worried-should-you-be/