Bright do not have paid subscribers and so they can't offer money off an energy bill and so as an alternative incentive they offer entry into a £1000 prize draw. As stated by National Grid "Each energy provider will have individual incentives for their campaigns"
and so they don't need to take in day adjustments into account but we don't know if they follow in the lead of Eon Next and just make it up as they go along.
Anyway I wasn't sure if I would yet receive a belated invitation to the Eon Next Energy Shift and so I didn't participate in any Bright Glow Delight event yet but I did make sure that I concentrated my power usage to the period of the event and I managed to clock up 4.74 kWh. Petty I know but that is my mindset on this subject.