I'm on a wildlife forum and have taken people through the whole sticky process of retuning, also had my mother on the phone and talked her through the entire process whilst watching my own freeview box crash three times on me... thankfully, I'm happy to report that 90% of the people I've helped have been ok, some have yet to retune (because of yesterdays little upset) and yes, our box is absolutely fine now. However, I've been telling people that it's GOOD to retune every so often and that it's a good habit to get into as it ensures they're familiar with their equipment. Had one enquiry about aeriels and suggested a splitter working alongside a signal booster (trust me, appropriate for the situation) and it seems that all is well with the world - except for the few that haven't retuned yet but will be doing it over the next day or so.
They're all aware that the retuning hasn't ended yet, but hey, if they're given the right info to do something in good basic non-jargonese, they can get through it... and thats good enough for me
edit: just had a report from someone retuning their TV instead of their freeview box.... hopefully, I've got them going in the right direction now