That's something I was wondering about while going around. The zoo has a single use plastic free policy I believe, so think most of the lanterns were either fabric or paper-based, with the lights being reused yearly. True though about it encouraging more visitors to go. In an ideal world, breeding programs and zoo-led conservation efforts wouldn't be needed, and zoos would serve no purpose than to entertain - which I'd not agree with, and would hope they'd not exist at all.