dchar

Never heard that ever happening on Lightning cables...so not a concern.

mcomer

The USB port(s) have a small 500 milliamp capacity which is barely a trickle.
As long as the device is media only (not a phone) it works very well, keeps
the charge up and plays nice bandwidth media. On 2015 and newer Lexi it
allows voice commands to playback tracks, "Play Eric Clapton!"

When using a phone to BT music and phone and traffic apps at the same time
it is best to let the device segue seamlessly between all those programs
and charge it from the 12v outlet. When the USB is involved the music
will travel that way and the Traffic App will be unable to break in then you
get a call which will glitch the whole thing. Not to mention that Waze and the
others consume a lot of power, beyond the .5 amp USB.

hziemba

I'm confused: if you have a cable plugged into the USB port, and the other end of the cable is not attached to anything, nothing is there to prevent shorting if the exposed terminals get crossed by a conducting material. Granted, it's not likely that the terminals will be crossed, but if they are, how can you not have a short?? Is there some kind of short protection, like a fuse??