Not at all. The open sights are well out of the field of view of the scope that close to the objective. The only way you'd have problems is if the sights are very high and get very close to lined up with the center axis of the scope. Remember that the field of view of the scope is very small that close to the objective and comes right out of the center of the lens.

As for why I still have the open sights on the rifle... well it's really that I've just never bothered to take them off. Not to mention that the screws are black and would look funny sitting above the bore and I don't like the idea of leaving open screw holes on the barrel of my rifle to catch dirt and moisture. I know that a gunsmith could fill the holes flush and make it look clean, but why bother when the open sights don't interfere with anything. The only time I definitely remove them if they are present is if they would physically interfere with scope clearance.

As for needing them in a pinch, I'm really not worried about that too much. Modern scopes are pretty reliable and durable, and in case I do manage to break my scope, I ALWAYS have a spare RIFLE, sighted and ready to hunt with, in the truck if I'm hunting more than an hour from home. To be honest, I don't even know if the open sights on my muzzleloader are sighted in, so they'd be nearly worthless to me anyway.\

Mike