Personally, I think that if the snake was in any danger of choking, it would most likely regurg the meal, and move on. I've never seen it, but it would seem like the natural thing to do, if a snake found itself with a mouthful of too much prey.
I saw a show on Discovery Channel one night, wherein a guy walking through the Amazon Rainforest came across a full grown(read: GIGANTIC) reticulated python tryng to swallow a man head first. Apparrently the snake was stuck at the shoulders, and was making a very strange "gurgling" sound, which was interpreted as choking due to the body of the man blocking the glottular-thingamabobby. The snake was put down, regardless, in order to retrieve the body for identification and proper burial, but, they never said if the snake was actually suffocating. :shrugs: