If a new lane appears which you have to enter in order to exit, once there I consider that "on the ramp" - your choice to move into it is clear enough.
I'm mainly talking about lanes which become exit-only up ahead.
To describe this more generally, if there's a situation where an inattentive driver could find themselves on a path they don't mean to take, then if you, the attentive driver, intend to take that path - signal to confirm this.