I also get requests to end auctions early. My standard response is " thankyou for your offer, the item has a number of watchers on it, so will let it run its course" and close with Kind Regards ****** I have never received a rude response to this line and the messager often ends up bidding on the auction. If I receive multiple requests to end early it usually means the starting price is too cheap and I often get a pleasant surprise once auction closes. On my store site I have a note on my BINs that all prices are firm. This keeps most of the low offers away.