From zooming in on the photo it seems as if the individual with the hood on his/her jacket is actually touching one of the macaques! It appears that the person is stroking the back of the primate, which is somewhat astonishing from the perspective of a North American zoo enthusiast. I cannot imagine a walk-through Barbary macaque exhibit opening up at an American zoo, and the monkeys would probably have lawyers out in droves for anyone that touched them.
I do believe you are correct! Rather their fingers than mine!
There were plenty of signs to tell you not to do this, as well as signs warning you to watch for your hat or glasses being nicked!
Barbary Macaques are a fairly widespread walkthrough choice in Europe - Apenheul and Neumunster spring to mind as further examples, as well as Trentham Monkey Forest, which is a whole zoo consisting solely of a walkthrough Barbary Macaque exhibit!