yeah, gravity feed is not an option. In fact, you might say it was a gay idea, but it would certainly be the death of whatever league implemented it.
On second thoughts, maybe the millenium series should implement it?
Oh, no hold on a minute, they would have to see someone else do it first, and then they could promise to do it the following year, and then procrastinate and end up not doing it, but not issue a decision either way, even putting 'gravity feed only' in the rules and then issuing a second verbal rule at their event saying that the written rule wasn't going to be implemented, but it wasn't going to be deleted either...