A) EXPECTED: When you have defined start + intermediate point(s) but no end point yet, would you already draw a line from start through intermediate, or do this only once the end point is added ?

And if you draw the line (first option), and submit ride without defining the end point, would you throw an error (for missing end point), or take the currently visible line (with last intermediate point as end point) as the ride route ?

Yes, you are right. The line should be drawn only when the end point is added. Without end point, an error message should be added.

PO:
Please select the end point of the route.
Por favor, selecciona el punto final de la ruta.