EKM,
You have gotten some very informative responses on this topic. Good stuff. I will add a couple cents worth.
IMO it varies with the conditions you are hunting in.
If you are hunting private land and the elk are going to remain undisturbed and are following a pattern leave them alone and let them come to you. Go play cards during the day.
If you are hunting public land the elk may be moving around a lot as hunters are pushing them. Then midday becomes as much a scouting exercise as anything. While you are covering ground looking for elk sign, be careful to maintain scent control and don't let your scent blow up to likely looking pockets blow your cow call once in a while and try to sound like a couple elk walking along and don't worry about making walking noises.
In heavily hunted areas elk will sometimes tend to gather mid slopes on the cool N or NE slope so look for likely areas to still hunt down slope or into the wind during the day. Where we hunt the elk move up at night to the meadows on top and then down to mid slope before first light.
Once you get to a likely looking area with fresh sign then slow way down and stay quiet, quiet clothing is a must, fleece works great, and watch the wind, at the slightest scent of you they will be gone. If the elk see you first they will blow out of their bedding areas giving you at the most about a 3 second opportunity for a shot. I have even seen a lone bull freeze and let a hunter walk right by within 40 yards of it. If you are unable to stalk quietly in likely areas stay out of them and go back in the morning and try the ambush.
Definitely wear a day pack with essential gear, but leave the noisy meat packing pack or frame in camp.
If nothing else still hunting/scouting during the day increases your time actually hunting which adds to the fun factor and that is what it is all about. If you are on public land and are getting bored during the day go for it.