This summer I reached SEA with 1.20 hours to go for departure of AS 153 to SFO. Since I had an international flight (onward from SFO via JAL), I was directed to the international check in queue - two queues of 12-14 people each, with two counters (out of 4) in operation. After waiting in line for 30 mins (with two people and a dog ahead of me), I was pulled out and asked to walk a few metres to a very different counter (along the edge of the terminal). The friendly staff remarked casually that another minute and I'd have been unable to check in my bags. I'm not sure why he said that given it was quite clear that I was waiting for ages.