I think the ginger ale would be strong enough to effect the line, but the other side of that is that it may be a moot point. Soda needs much more carbonation than beer, and any soda that is carbed like a beer willl seem flat. With that much carbonation, you'll need more beverage line than your standard beer serving length or you'll be pouring foam. In other words, I think you need about 15 to 20 feet of line for soda, which is too much for beer, so you probably neeed a dedicated line anyway.
The balance to that is that you can turn up your serving pressure closer to 15-20, so it's not really a slow pour. The problem with that is that you would need either a secondary regulator or a dual pressure regulator. I have a dual pressure regulator so I can serve soda at 20 psi.