Events capital = big returns, right?

The New Zealand Herald today is reporting that Auckland is a more successful city than Sydney at attracting and hosting major events. Auckland Mayor Len Brown says:

"Major sporting events are big business and bring substantial economic benefits to the host region, so there is fierce competition globally to secure events."

There certainly is fierce competition all right - but not a whole lot in the way of compelling evidence that the economic impacts of events are as substantive as commonly thought. Nevertheless:

Auckland's annual budget for securing top sporting events has risen from $6 million five years ago to between $8 million and $12 million now, said Rachael Carroll, of Auckland Tourism, Events and Economic Development (Ateed).

and

Ateed's figures show that events in 2011/12 produced a net return of $28.9 million to the Auckland economy. The current funding year's events are on track to return $30 million.

I wonder what the term net return means? Is it returns to ratepayers? Is it returns to the Auckland Council? Or is it good old economic impact? I suspect the latter. There are all sorts of problems inherent within the calculation of economic impact when applied to a sporting event. In academic circles there is very little argument in favour of sports events generating substantial economic impacts. I've researched in this area in the New Zealand context (see here - note that this paper is presently under review for possible journal publication) and found that the major events are underwhelming in terms of what their realised impacts were on host cities. I'd really like to see an estimation of actual benefits (that are not economic impacts). What are the public good benefits? What are the consumption benefits? Who do they accrue to? What evidence is there to suggest that this is the best use of $12m of scarce Auckland City funds? If it is there, I'd love to see it.