Some other very common mistakes include assumptions that people:
* have a physical address
* have one physical address
* use a mobile phone
* use any sort of telephone
* can access the Internet
* use email
* know their mother's maiden name
* have had a pet at some stage
* attended a school (and other password recovery question options...)
* have an occupation
* have one occupation
* have a credit card
* have a bank account
* have 20:20 vision
* can read English and understand what is expected of them in a form
* know their own date of birth/age
* know their own name
* know their place of birth
* have money to print forms, send letters or make phone calls
And importantly, assumptions are made that people will will agree to provide information that is not required for the interaction/transaction.
Common sense usability is to not ask unnecessary questions or collect unnecessary data.
UK readers... Please remember that students are 1 of the only groups to officially have 2 permanent addresses. Furthermore, it's illegal to collect unnecessary information.