It is rather confusing,isn't ti?
Let me try and explain (courtesy of a friend in Plymouth,who was lucky enough to be recorded).
As Paul Martin says,ALL the people that come along ARE seen,and their items valued.
Sadly,as only 7(?) items can be shown being auctioned,the others are left to take their items to auction (if they wish) and auction them personally.
My friend said she wished she hadn't been recorded,as she felt obliged to agree to them being filmed being auctioned.Whereas the persons with the non recorded valuations could decide for themselves whether to sell or not.
BTW,my friend only just passed the lower estimate at auction,and so was a bit miffed.
No pleasing some people!! LOL