Makes sense that they will keep guests away while they try to get the orangs used to the exhibit. It's all of the orangs first time outside (Puppe in 49 years). The outside world is big and unfamiliar to them. Keeping guests away removes one potential additional stress for the orangs. Help them get used to their new home faster if they feel safer in it. Plus this is a brand new exhibit and the zoo is home to 7 evil geniuses. If there is a way to escape one of them will find it. So safety is a consideration as well. I remember when the savanna opened the baboons were able to climb out of the exhibit. And there was the time the lemurs let themselves out to mingle with guests. Probably better to avoid that and give keepers as much space to work with as possible should one of the sneaky monsters outsmart the escape proof design.