I believe the facebook crawler will crawl redirects, such that a URL that results in a redirect to a blocked domain is still going to get blocked.
(Even if it were a satisfactory solution to say "message all your customers and tell them they have to start using the new domain for ticket sales, including for events that are already promoted with ongoing ticket sales" which of course it isn't, although I follow you that it would be perhaps better than nothing).
(Even if it were a satisfactory solution to say "message all your customers and tell them they have to start using the new domain for ticket sales, including for events that are already promoted with ongoing ticket sales" which of course it isn't, although I follow you that it would be perhaps better than nothing).