Long answer: This feature was implemented and I used it personally some time ago.
I disabled it as it put extra load on the server, but nobody else seems to be using it anyway.
If you wish, please open a support ticket and I'll enable it for your account and explain how it works so you can use it.
I've recently added the security number enhancement device to my ebay password login. Can myibay snipe still place a bid if you don't have the current security device number, or will the snipe fail?