Borders, highways and rivers

I have some questions about mapping a border that follows the center of a highway and then it continues in a river. The highway has a bridge over the river with bridge=yes, layer=1.

Do I put a common node between the highway and the river so I can add both to the border relation? In this case, will there be routing problems because the highway intersects the river? Is there another approach?

You should not connect the river to the highway if they are not connected in real life.

Are you sure that the border is on the highway-center ?

The best solution IMHO is to draw a separate border-line using the highway and river nodes.

Are you are suggesting to draw multiple lines using the same nodes? I thought that the relations were used so this situation does not occur.

In this special case: yes.
because the common node would be wrong.

Since the border has an angle just at the point where the highway crosses the river, it appears that the node in the intersection is needed anyway to represent the border.

I still fail to see why it is an error to have a node in the intersection between the river and the highway given that the highway is marked with layer = 1. So it is clear from that context that the highway and the river do not touch.

I quote the docs for the keepright-tool:

So, what is the solution in this case? By the way, the tool Keepright does not show any error here: (an example of the problem posed in this thread).