Indeed, and if the issue is not a faulty seat but a curtain move you won't even be able to see or move your seat, and the same if you are already checked in with the new system (even if you didn't issue the BP) unless you keep trying endless times till you are lucky enough to fall back to the old system (which is rarer and rarer). So when I was moved from the 1K which I had booked for months to 4E, I was very unhappy indeed especially as I knew there was another seat that could be booked and was available. GGL claimed they were unable to help (they have managed in such cases in the past) so I ended up going to the airport far earlier than I needed and wanted to, but thankfully was still able to snatch 3K that way before my 13 hour flight..