Ok - well, even though most of what you just said didn't make that much sense - I'll try and answer to the best of my ability..
You mention "this Saturday" - you meant, Saturday 3rd September that had just been correct? The whole rumours of Urban etc? It's quite easy to imagine someone starting a rumour of such a party out of desperation or dillusion that the promoter may then be 'forced' to put something as a result of the rumour being spread. In no case would that ever happen - planning a gig takes months.
Do promoters take feedback onboard?
I'd like to think they all did - I know Central Promotions does. I know Yellow Brick Road do. I know the people who ran Spectrum also do.
I guess it comes down to the extent of the request?
Typically people have to be mindful and not too opinionated when it comes to feedback about gigs - particularly in the Underage scene.
For example, if the cooling at the gig was truly a problem - make it very clear that, although the lineup, the venue, the staff etc were all super-wicked, the cooling was something that was definitely in need of upgrading (ie. Hiring fans).
Because what you say about a gig, vastly contributes to the reputation a gig can have - it is VERY important to be extremely mindful of what you say, especially considering that the scene and dance music in general is flourishing - and you've got promoters giving you guys what has been sought after for years.
There are few promoters who will continue to inject their time and money into the less profitable market known as the underage scene, purely based on the fact they need to pay their bills - and there's no money in the all ages scene, if you've got bills that need paying.
Therefore you get left with promoters who are utilising all the faucets they can possibly get their hands on, trying for new themes, ideas and approaches to things - just to create an epic atmosphere and regular nights where underage youth can enjoy a safe night out, in an environment with music to suit.
When you regularly show your appreciation for that in feedback threads, and by spreading the word, and treating every gig like it's the last underage gig that will ever be put on for you - that's when you start getting promoters who will go that extra step to ensure the next gig is x10 better. It really counts when its positive feedback - it helps making a very unprofitable business, seem like it's still worth doing!