This came up in relation to our use of the Questionnaire module, but I'm managed to convince people we should change it only in the module that we're hoping to adopt!

Basically when you view the responses and download them, you should be able to see the user's full name as well as their username and IDNumber. The latter is not currently available. We use this field to store the user's personal identifier which can be more useful than username for some forms of analysis.