Glasses

From Wikipedia:

Bokito may have become frustrated because the woman, who appeared to show interest, repeatedly walked away. Van Hooff speculated on what might have happened had she remained still rather than resisting. "I think he would have given her a few slaps on the back. And then, yes, he might have done what male gorillas do with female gorillas."

Sure if you want to set the game to easy.

No. We'll just leave that to the zoology interns.

He became the subject of considerable international media coverage after escaping from his enclosure

Wait, so their enclosure was shitty enough that the gorilla could've left any time but didn't until he was provoked, and their solution wasn't to fix the cage, but to make everyone wear silly glasses?

“The injured woman had been a regular visitor to the great apes' enclosure, visiting an average of four times per week. She had a habit of touching the glass that separated the public from the gorillas, whilst making eye contact with Bokito and smiling at him. Zoo employees had warned her a few days earlier to keep her distance and avoid direct eye contact with the animal. This sustained staring is thought to have contributed to the attack. Although in humans smiling is a friendly behaviour, in gorillas it is a practice that is discouraged by primatologists, as apes are likely to interpret teeth exposure as a challenge or a form of aggressive display.[22] Speaking from the hospital in an interview with De Telegraaf she said; “He is and remains my darling. Since he arrived at Blijdorp, I have made contact with him. If I placed my hand on the glass, he did the same. If I smiled at him, he smiled back.”

Also, these glasses actually make it look specifically as if the wearer is looking away, whereas sunglasses just make it hard to tell if/when the wearer is looking at you.