No they can't. You must be one of those useless drivers who says after an accident "he came out of nowhere". Gets your eyes tested.
Non use of turn signals is easy. If they don't indicate, they don't get to go that way, just pull straight in front of them. If they hoot at you, wind down your window, use the wanker sign, then alternately flash your indicators to educate them.
And if the sun is obscured by cloud? I just put sidelights on when I feel it would be difficult to take a photograph without long exposure (so people's vision will also be slower), then I put dipped beam on when I need to light up the road in front of me to see where I'm going.
No (enforced anyway) rule here about rain, I never use mine unless there's heavy spray off trucks.
I also never use fog lights, as they're identical to brake lights. You come up behind someone with rear fogs on and you don't know when they brake.