> Many people, including many people on this site (and, yes, including myself) wouldn't think twice about plugging into an available port if they need a charge. Maybe I don't plug into an unlabeled port in some random location where it doesn't look like it belongs, but honestly I wouldn't think twice about charging at a designated area at a conference.
If you're already committed to carrying Yet Another Accessory, then why not just carry a small portable charging battery. Some models are not much larger than that USB connector, and could charge the phone more than sitting babysitting a charging phone for an hour.
Yeah, I normally carry bigger portable batteries but I've got a bunch of small ones that I've typically been given by vendors which are probably good for at least getting a phone off life support.