I am converting to XenForo from vBulletin 5, which is the absolute worst commercial software I've ever used. I have thousands of messages that were actually SPAM and were "soft deleted" in vb5... but when converting from vb5 -> IPB -> XenForo, all those messages get transferred and don't get marked as "deleted". So if I don't get this fixed I'll reintroduce thousands of spam messages to the internet again. Sigh.
The fine folks at Todo10 have been doing the conversion for me but we ran into this snag. If we can mass prune messages from banned users and remove them permanently in XenForo, that would be a workaround. But I'm open to other suggestions too. The vb5 software doesn't have any mass prune capabilities or addons. Not sure about IPB.