
They would be ruled as a separate competition, (after all they are really as they do not count towards progression to group or BIS, so are a separate competition to that of BOB, leading to Group, leading to BIS) same as other events held in conjunction with the show.
At the moment support for stakes classes is very low.
I remember being in Houndshow stakes classes filling the ring, and on Saturday just 5 in bitches, and 3 present in dogs ;) didn't make getting a place very satisfying, though the £5 prize money was enough for a snack.
The second class entry fees are now so high that knowing one might have to miss the stakes anyway makes people loathe to waste £5 per class, to enter stakes alone at CC or even Non CC price with no real win, also doesn't encourage participation.