I was asked if it was allowed, so I asked Dyane. Her answer:
Yes. But the character history on NC will be different than the one on NorCon. If the NorCon character gets promoted to let's say an Wi2 but on NC is a wingrider, his rank from NorCon is not accepted here since it is a different game. Does that make sense?
Those people who have migrated and said they have retired [...] lost their status on the game because they have retired and new people have been put in place. If they want to come back, they are welcome to but they come back as normal riders/weyrlings and have to transfer back in since they said they were leaving, i.e. transferring out. It is the same thing as if they retired and left the game altogether.
It's nothing different than what normally happens. People leave, new people are put in place. If people tell us they are leaving, then new people get put in place faster. :) Same thing. We don't do idledesting every three months since our space issues aren't bad but we do try to @idledest every 3-6 months of inactivity so that will happen again.
We're so not going to be if you play on the other game, you can't play here. That would be absolutely ridiculous. :P