This will probably be an unpopular opinion, but I actually thought the driver was exceedingly rude. He clearly took advantage of Kalanick being in the public eye, and thus a "target". Filming him without acknowledging it was totally immoral, it should reduce any fair person's bayesian priors as to the credibility of the driver. I'm no fan of Kalanick, but I thought he comported himself reasonably, taking the time to…
It's definitely illegal. It's not immoral to film it necessarily, it is maybe immoral to release it without permission. But at some point you have to admit that it becomes "public interest" to leak information, even if it transgresses those moral standards. As an extreme example, if you had managed to covertly film Kim Jong Un, giving insight into the inner workings of the hermit kingdom, would it be immoral to make it public?