I think you're right - respecting your local residents and their views is key. As it happens we have used the discounted & free tickets on more than one occasion, but even if we hadn't the fact that the Racecourse has actually bothered to make the offer shows they appreciate that some of the locals might not be too happy about the noise, and are trying to do something to appease them.
As Shale Searcher said, some may view that as bribing the locals to stop them complaining, but hey as a local resident I'd be happier to be offered a 'bribe' than nothing at all!
There are always going to be some locals who aren't happy regardless, and no offer of cheaper tickets is going to change their mind, but I'd like to think that for the majority the offer of something at least shows their feelings are being considered. As speedway becomes more & more of a minority sport, the more that the Robins promotion can do to keep the local residents sweet the better in my view...