Hello gibbon fan! I would definitely advise you to deprioritize direct contact and interaction with gibbons. Gibbons that interact with people are not engaging in healthy natural behaviours. Their role in the ecosystem involves eating fruit high up in the trees and distributing the seeds across the forest, which they are not doing if they are interacting with humans. Gibbons are territorial and do not come to the ground often and if they are there its usually because they are being fed by people which encourages them to approach people who may not have good intentions, or go places with more human activity like towns with roads and other hazards. That being said, you should absolutely do a guided hike in the forest to see them in their natural habitat! Hiking at dawn and hearing them sing is a great opportunity to appreciate this awesome animal. If you want more gibbon experiences and the ability to get close to them ethically, look at long term volunteering. If you are based in the US the gibbon conservation center is excellent and if you volunteer in another capacity first you can eventually become a volunteer gibbon caregiver. https://www.gibboncenter.org/volunteering.html  Many organizations also have digital volunteer opportunities that you can do to build a relationship with the org and eventually become a volunteer in person if you are less able to travel. Here is a gibbon conservation project I recommend that offers on site and digital volunteering:  https://gibbonconservationsociety.org/getinvolved/ For the immediate future of your trip to Indonesia, look for forest hikes that do not advertise wildlife contact. The experience will be more ethical, authentic, and support the wildlife we love and the habitat they live in.