No. You can't see them. However, all is not lost. You can get into the Marcus center for free if you're willing to sit on the grass. You'll need to buy a pass into summerfest and then get your hand stamped for the grass area. They only have a limited number of grass seats so if it's a really popular concert you'll want to get down there early. It's not uncommon for there to be a line of a hundred people when the festival opens. They'll rush to get their hand stamped and then proptly leave. The summerfest ticket used to allow you to leave and then come back.