They were indeed oversubscribed many times over. But those who were lucky enough to get tickets had the opportunity to give them back if they changed their mind for whatever reason, hence there has been a few tickets popping up for sale over the last few weeks.
As reported in The Telegraph http://www.telegraph.co.uk/sport/rugbyunion/rugby-world-cup/11870000/The-great-Rugby-World-Cup-rip-off-fans-hit-by-hidden-price-increases-at-stadiums.html
Some of the quotes:
"Eleven of the 13 RWC venues or their catering suppliers provided some degree of...