I guess that's where you and I differ. Personally I would never take a right turn with a driver making a legal left hand turn onto the same street with two lanes and "assume" that he wouldn't for some reason come into the right lane. I guess that is why it doesn't bother me if he does.
As far as merging with traffic, again I don't merge if a car is close enough to hit me when I enter even if he is in the far (left) lane and I would be entering the right lane only. Just me I guess.
Its more of a geographical issue than personal preference or habit, I believe.
In So Cal it was not uncommon to see people moving at freeway speeds with 10ft between cars, when possible.They generally did it like it were a NASCAR event and got away with it. People there are more aware and more skilled, until the streets get wet then it all goes to hell. Since they don;t see water for 10mts out of a year their skills are inadequate on wet roads but fine on dry streets.
In Tex, these idiots tailgate and will bang into each other like their cars were magnetic, and then go right back out and do it again with no lesson learned. I see soccer moms around here doing 70 on 2 lane country roads in the rain in the minivan with a coffee in one hand...and 3 kids in the car.
Thats why the hillbilly gene is dominant around here....too many kids have to grow up without parents because they killed each other off in stupid car accidents.
I'm just saying that the traffic rules may be well defined but there is a lot of latitude given due to congestion and cops will allow things to evolve as they will, as long as common sense is displayed with some level of skill. Like the merging thing....its timing and judgement. I would not attempt a rt at the exact same time as someone making a legal left, even IF there were 3 lanes, but I would make my rt turn in a way so that the timing would determine where I ended up regardless of where he ended up. Since I know better than to depend on anyone else, I have to work harder and actually think about it so that I would end up behind him, never ahead in case my car was unable to get out of his way.
That still does not make it ok for the guy making the left to just wander across lanes where he wants.Knowing where he will be allows other traffic to flow efficiently. Having to wait for someone to get in a lane or pick a lane just holds up traffic in heavily congested areas. There are places here where the parking lot exit is the freeway service road, and traffic is moving past at 65 mph off the ramp onto the service road or feeder street, and its thick too. Timing is critical and having people stay in their lane is essential. Otherwise, someone gets hurt.
Thats why MANY left turns (and other turn lanes) now have dotted lines that go directly to the next available lane so there is no doubt as to which lane to end up in. Around here they have white lines near certain traffic lanes and its illegal to cross a solid white line. You must wait until its broken or dotted. People ignore that like the double yellow.