I am not sure if this is a coincidence, but I signed up yesterday for BigPipe and got the confirmation email. Somewhere around evening, my connection with Telecom went dud. I did a bit of basic troubleshooting (resetting modem, connecting directly) but didn't work. Their tech support confirmed that it looked fine from their end, but couldn't proceed to do any further tests until I was home to check the modem. Unless the switchover has already happened, then this is something else.
I guess it's possible Chorus have been a bit over-eager and done the transition super-fast without telling us.
But if Telecom tech support seems to think all is fine at their end, then that's unlikely, as they would have had a disconnection notice.