To which I perhaps should say, "Thank God", because if you were unlucky enough to get four of them in a game, then what? 
Still, I did get my second Slowdown (-25% speed ALL RACES) Mega Event a while ago, and I am still at the initial 25% penalty. I don't have a before and after save right around the event, because it was random. But I thought I should mention this to the devs in case they wanted to look into this.
*PAUSE*
Please don't make them stack, BTW. As I said, what happens when there are four Slowdowns running? 
