I would think it depends on your view of the world and your safety. From my opinion regarding myself and my safety, I wouldn't cancel because I know how to handle myself and I am not worried that I will become a statistic. But that doesn't mean no one else should. It should be an interesting time in September, but expect a lot going on because of the elections. I think that targetting foreigners will be less than just general protesting, but who knows.

There are people here on FT that chase revolutions. I don't remember the guy's name. There are others who won't go to Bangkok alone because they are afraid of white slavery. I do remember her name but she will go unmentioned. Most people fall somewhere inbetween. I think you just need to ask yourself how much risk youre willing to take and then go with your gut. I didn't feel threatened at all in my week in Cairo except for all the obnoxious tourists and the touts wanting to sell me their mother's mother.

I will say that if youre going to spend your time constantly looking over your shoulder, consider going some other time. The last thing you need is to be paranoid for a week.