As far as a lot of the general public are concerned, any loco with steam coming out of it may as well be Flying Scotsman or Thomas. Personally, I always enjoy when locos taking on guises of other engines: Firstly, it's often done temporarily as a way to reenact a historic event or railtour, which can be a big draw for galas without having to spend far more on an extra visiting engine, or it's done to honor a certain person in the railway world (Take 55009 currently running as 55013 for example). Secondly, it's a chance to see locos running in identities that you otherwise would never get chance. I was born far too late to have seen steam (Or even BR Diesels), so the only chance of seeing a scrapped engine now is to swap an identity. Plus it's far more exciting than just seeing a nameplate stuck on a wall in a museum! As for instances like this, it's unlikely 80100 will ever steam, so this may be the only way of seeing her identity run. And with the loco having been resident at the Bluebell for sometime, it's nice to give her identity some time in the spotlight, considering she's spent good portions of her preserved life sat in sidings out of sight. That's just my two cents anyway, it's not to everyone's taste sure, but when it does happen, it'll always get my head turning (And perhaps more importantly for heritage railways currently, wallet out of my pocket)!

a) This was an enthusiast event. b) The event guide will have explained what was going on.