It is very sad. I believe if people commit to an event - particularly a charity event where they are promoted as being there, they should have an extremely good reason for bailing. Both Tim and Mikayla tweeted that they were attending at some stage, or retweeted the event. I'm not sure about Jade.
Jade didn't retweet about it or even acknowledge it. They also tagged Tahan on twitter at one stage, and Maddie on Facebook, and implied they both were attending as well.