Hey govind440,
Unfor, there is no clear process as to how it works and no committee would divulge such info. I believe for someone on the WL to get an offer, depends on many factors at this stage and that includes, diversity and quality of applications in R4 etc... Take for instance diversity: a candidate from country X where 'X making up 25% of the incoming Jan16' vs. 'X making up 2% of the incoming Jan16' -- the former has a lower chance getting off the waitlist for the sake of diversity keeping all else equal. It's more complicated than that for sure.
It's a wait and watch for the time being the way I see it. As for the rejection etc... not quite sure on that, I don't know if they would keep WL profiles active for the Sep intake but I doubt. Considering that R4 notifications are due by Oct 9th and they've already reached out to few so I'd give it another week or so, I think they've already crafted their class and now awaiting acceptances. The only chance at that stage would be if they've encountered declines on their part then this might open to some getting off the WL.
best to everyone.