I have a lab who I have been training for hunting and working a bit. Its almost necessary as he seems happier when I have him working. In any case, I dont ever use word commands just hand commands. He is a Lab and if I didnt make him stay he wouldn't! especially when retrieving. An elder gentleman told me once that "on either side of a lab's brain are two tennis balls and thats whats most important to them".lol Making them stay is in my view another way of teaching them some self disipline and additionally letting them know that esentially you are the pack leader.