There was crap lag in the game before RF started and during non WB weeks. It's probably their servers or some cheap ass node down the road from their US facility that was bought from Wallmart.
Many of the Americans in my guild have piss poor ISP's with connections that drop when it rains and it wouldn't surprise me if the infrastructure in the US is patchy at best. It's the land of the free and that's probably what large parts of their network is worth.