The buzz phrase is "economic impact assessment" (EIA): as past organiser of a festival which was and still is, thankfully, in receipt of some support from the local Council (and we know that may not last for ever as Council budgets get ever reduced!), it is almost a pre-requisite that we do ask people to fill in these forms - as Nigel said: they are usually couched in such a form that they can be fed through a scanner to analyse hundreds of results quickly rather than manually, hence your tick-boxes. Without such feedback, many festivals would die or at least, have their funding reduced. And there is an approved wording/format for such EIAs.
I do agree that it is a bit ridiculous to ask people to fill in a form at every single event, especially if they have bought a whole week or weekend ticket, and the stewards issuing forms should perhaps be less zealous in trying to get everyone to fill in forms at every single concert or workshop and allow for this.
The other purpose of these forms is for feedback to the organisers, and in my experience, the inclusion of a freetext comments section can be the most enlightening and helpful in planning future events (as well as, on occasion, being ludicrously wide of the mark - e.g. "well what the F did you expect???" might be our reaction)