For me it was fairly easy to tell when the cush drive rubber went. The chain started to feel like it was slipping coming off the line from a dead stop. I didn't have that much play either, maybe half an inch or so.
Over the almost 3 years I've been on ba.com, I've read a handful of cases like yours...where the rubber wears out quickly. I sympathize with your plight, and I hope your dealer takes care of it. It's not something to be taken lightly, because it can cause excessive wear to your chain, sprockets, and even the gears in your transmission.
