AND if you read the price tag attached and the requirements they ask for, for the sale to happen, you would be silly to spend that sort of money on a cat to allow to go wild. These sort of cats are bred for there tempermate and look - for showing!! NOT for release in to the wild.
I see your point, it may take a while before they become common enought that it becomes likely for them to be able to escape and potentially "improve" they feral cat gene pool. Allowing them in is just creating a problem for the future. It may not be for another 20-30 years, but no one can say it will never be a potentially disaterous problem for our wildlife.
Go use goggle and read they front page it will tell you a lot about the people they are and the animals they breed - you should not bag feral cats but there feral owners, they have to start some where and it is usually the owners.
The cats are the problem, its quite simple. Go out in the bush you will find cats and none of them have owners, if one fertile savanah gets out it could have massive implications for our wildlife. It wouldnt be far off being one of the worst animals to introduce here. Also most ppl dont bag feral cats, they normally just shoot them and perhaps even cook them up :lol: