My vault would be as follows;
There are alarms before all food dispensing. Food would only be dispensed once a day. After 5 years, food would only have a 2/3 chance of being dispensed when the alarm goes off. After 10 years food would only be dispensed 1/3 of the time. 20 years later, food would only be dispersed 1/6 of the time.
This is followed by babies being kept in a nursery and fed only by a non-speaking Mr.Handy until the age of 5. (100% food/bell ratio)
They would then be transferred to the boarding school area. This is where they learn basic reading and writing and math skills. (2/3 food/bell ratio)
At age 10 they would go to the secondary school part of the vault. This is where they are assigned a profession to major in. (1/3 food/bell ratio)
At age 20, they are moved to the advlt habitat, where they are expected to work in their assigned fields. (1/6 food/bell ratio)

My thoughts are that you would be allowed to ring the bell when you entered and are given the choice to either feed the inhabitants or to starve them. If you starve them, they will all become hostile and try to kill you. If you feed them, they become friendly and will trade service for food. Even with a few followers to choose from.