No - I used to live and run in Indiana. I ran 1/2 marathons all the time and I never carried water or wore sunglasses. I don't know if its because I was young and stupid and lucky or because the humidity there is so much higher but I never had any problems. I did drink at the water stations when I ran races but my rationalization for that was: I was running faster since it was a race. My question to your friend would be - did she show signs of dehydration either during the run or after? If not - she actually could be OK.