As I said - Kevin from UBrit telling the same:
But seriously, I don't think this was their wedding at all. It really was their engagement party. Of course, media made a big deal when they saw that. You know how the pop princess can shock and tease... You remember how Lynne said Britney's wedding dress would be so beautiful and how the event would be so huge. Also, Brit clearly said it would be her fairy tale wedding. So why would she wear some pants and a top and have chicken fingers for dinner? Look, I think this is a huge prank to keep paparazzi away for the big day.

From me:
Again - it is all CONFUSING...Britney may tease us....But she will not keep away paparazzi..It all looks serious..That's why - it can be true...Time will show!
Maybe it was just a party........

Here is the news from Official Brit site ----> WWW.BRITNEY.COM
Britney.com: Congratulations to Britney and Kevin on their marriage! Get all the details on the wedding and the newlyweds' future plans in People Magazine hitting newsstands Friday 9/24.

So...It was real wedding...............................................Oh my god...Confusing.....
Not AMAZING wedding..But - without different people...
Maybe they () are teasing us even on her site....:D
And if she just got married yesterday, why would she not come on TRL to promote My Prerogative, since she doesn't have to plan for her wedding?
But seriously - spokeswoman might have said that to make people think the wedding was later.