It's perfectly understandable that, for whatever reason, some people might have to cancel their participation. Some people register and then don't respond at all, not even to personal messages or emails. We expected that; it's just the way things are these days.
For this reason, we have cleaned up the registration list; those who have "unregistered" and those who have "disappeared" have been removed, so the list is now up to date. We would like to express our sincere thanks to those who unregistered "properly" and thus, although regrettable for themselves, enabled others to participate.
