Im always hearing people say they were upgraded, how does this happen? if it isnt offered to us, can we pay there and then to do it and do they have good deals for this?
I really don't know how this happens. Last year when my DD, DGD and myself went to check in at the BC, one of the CM's came up to me and after checking who we were told me that we had been upgraded to concierge (I think it's called club now). It was totally out of the blue, we weren't dressed smartly (after a long day's travel who is?) and she must have known who we were and how many there were of us before we checked in. I've never asked to upgrade because I think basically when I'm checking in I'm too excited to think about it.
Getting upgraded is at the discretion of the CM who checks you in really. If you offer to pay for an upgrade they will charge you what ever the price difference is and I've never heard of them giving a cheaper rate.
We were given the concierge upgrade for the Polynesian. I know though, that it was due to the background work of a CM we have come to know. He arranged it to happen (he wasn't on the day we checked in). Otherwise, I'm pretty certain we'd have not had such a nice upgrade!
When using DVC points to stay at a non-DVC resort, it's my understanding that no upgrades can be given. I don't know if that is the case for any resort, but the CM I'm talking about told me if we booked with DVC points he'd not have been able to do the upgrade.