The International Zoological club is "locking in customers".
In financial matters, vendor lock-in, otherwise called as proprietary lock-in or customer lock-in, makes a client subject to a merchant for items and services,
unfit to utilize another seller without significant exchanging costs like in
the given example members are required to pay an initial fee to
cover the first two years of the subscription when registering with the club
which makes a significant financial loss in case an individual decides to
change the club or services provided by it.