Hi there
I wouldn't raise my rates for such an event, but then I feel my rates are at a level where it's not feasible to raise them. In this economic climate I personally wouldn't think it wise, however I don't know what your rates are so I can't really comment.
With regards to rates, it's what you feel is right for you. I don't see how an event can have any bearing on what we should/shouldn't charge although of course you can use it as a marketing tool with the theme of the event of course, such as the football where girls will have pics taken in football outfits etc etc.
There's been a lot of adverse publicity regarding prostitution and the Olympics recently, although this was more in reference to trafficked girls from abroad, so perhaps raising ones rate wouldn't go down too well but as I always say here, it's entirely your decision as we all market ourselves in different ways.
Who knows if we will be busier or quieter? Perhaps your outlay on a pro shoot won't be necessary as you will be busy anyway? Worth thinking about.
Good luck