Society committee asking for 5k extra as deposit

Hey, so as you know when multiple tenants are sharing the flat and someone gets replaced before the end of agreement, the new tenant comes without the name in agreement. So the society have decided to collect 5k extra per head from bachelor tenants and said that they can collect their money back whenever they leave. This is done so that society committee will know when a tenant is leaving the flat and a new tenant is coming. Our owner is a chill guy and said you'll definitely get your money back, but what do you think? These society rules are getting out of hand!!