Hmmm… Isn't that a little naive? I mean, yes, transparency is good. And if someone chooses to be transparent, I'm all for it. But, as a matter of fact, most large sports tournaments are anything but transparent. They are run by professional organisations for their own ends, and being as profitable as possible is often one of those ends.
Why would some golf tournament, or tennis tournament, or whatever allow anyone who asks to stick their nose into their financials?
If someone wants to run a pinball tournament for profit (good luck to them!), I don't have a problem with that. If players feel the tournament is well run, worth their while, etc, they'll attend. If they feel that the fees are too high, or the prize money too low, they'll stay away. If someone makes a ton of money by running tournaments, it won't be long before word gets around and other people will join in to try and make money too. And that increased competition then ends up levelling the playing field again. Market forces in action…
So, I don't think there is any moral obligation on a tournament organiser to disclose anything. Kudos to those who do (and, obviously, it's essential that they do for things such as charity events). But, on the face of it, why shouldn't someone make a profit after putting a ton of effort into organising a venue, getting machines together, promoting the event, running it, and so on? I would think that they deserve to get some money for all their hard work.