The night's no longer young ...

We often watch the BBC news at 10 pm followed by the London news, from Louisa Preston. Why is it that at at 10.34 pm the lovely Louisa says at the end of the bulletin, "Enjoy the rest of your evening"? By that time I've already fallen asleep once in the main news and all I can do is struggle up the stairs to bed! It must be my age ...