If you fine in the keg and cold crash, the vast majority of sediment will drop to the bottom of the keg. If you pull a half pint of beer, you'll pull all the sediment out of the area around the dip tube and there won't be any more sediment to pull. Some beers take a while to drop clear, so if you're not waiting long enough, you may continue to get sediment, but you can always pull a small amount, dump it and then do your pour.