Power Ratings

I was looking through my Parts Express catalog, noticing how all their tweeters have maximum power ratings that are low in comparison with woofers from the same manufacturers. So why aren't tweeters being blown out left and right? Is wattage handled differently from impedance in that the crossover deals with impedance on per-driver basis, but with input power ratings as if the two drivers were being wired in parallel? This is a mystery to me.