I don't know anyone who was included in the pilot so I can't comment. Experience tells me if you don't claim you don't get. I recently had to make an unclaimed money application for the compusory acqisition of shares I held in a defunct company two times over.
Up to date bank details will be critical for automatic refunds. Dave still may not have claimed or received his Tax Credits so to claim BS is a bit rich IMHO.
