Perhaps a topic should be locked in the Wiki while someone else is editing it and unlock it after a set time - for those editing, you could use AJAX to make sure it is still locked. And/or maybe a diff/merge feature.
FlexWiki normally uses an optimistic locking scheme - it doesn't claim an exclusive lock when you edit, but when you hit "save" it checks to see if anyone has edited the same page since you started, and if so it forces you to do a (manual) merge.
Not sure why this isn't happening on the Channel 9 wiki. Possibly that feature was disabled to cope with the load?
In the meantime we can do manual workarounds by looking at the version histories. Thankfully this is the only page I've seen this happen to in the entire history of the wiki