Not a Spice Girls fan, but just want to highlight the Daily Mail's usually biased reporting (lies).
"it appears a number ticket holders had second thoughts about seeing the Spice Girls perform in concert last night"
So, the Mail reckon that people who had bought tickets did not bother to turn up. Even if that is true (which is unlikely) that is still a sell out.
Toilet and refreshment facilities are notoriously slow at big Arenas, if the photo of the empty seats was taken a few minutes after they came on stage, then you will see empty seats. As seats are sold in rows, the disparate positioning of empty seats would seem to confirm they were momentarily vacant by late arrivees.
I have looked and tickets were on re-sale for high prices, not likely if it wasn't sold out.
http://www.dailymail.co.uk/pages/live/articles /showbiz/showbiznews.html?in_article_id=501100 &in_page_id=1773&ico=Homepage&icl=TabModule&ic c=picbox&ct=5
In answer to your question, I am not bothered what happens to the Spice Girls. They can afford to do what they like, so I am sure they will.