If you have a powerbank with you (which may be empty), you could also charge the powerbank using the untrusted power source, and at the same time charge the phone via powerbank to "sanitize" the source. This way you could still benefit from quickcharging.
Yep, this is what I usually end up doing while traveling. The battery doesn't care about the data lane even if the charger is somehow malicious, and my devices get pure juice.
