granted that there are no unconsenting people in the scene, or that they will not be recognizable in the resulting images

Nope. That's neither the law nor the ethical requirement. If it were, the entire genres of photojournalism and street photography would not exist. Things may change if it's for commercial purposes such as an advertising campaign, or if it forms part of a pattern of stalking or harassment or similar, but the general baseline is exactly as I said: there is no expectation of privacy in public.