Recently I came up with a password requirement rules as follows:

The password must

• be 8-16 characters
• contain at least one number
• contain at least one lower case letter
• contain at least one upper case letter
• contain at least one of these special characters: @#$%^+=*_.?
• cannot start with a ?
• cannot have the same character repeated more than 2 times in a row (e.g aa)

Everything except can not start with a ?, not letter a, is acceptable. Does anyone know a special reason for this requirement?