Do teachers still tell students not to say "They say summer's going to be cool" or "They say magenta and turquoise are the hot new colors" because "they" in this usage is too indefinite? "Who does it refer to?" was always the standard question my teacher posed. "Who are 'they' and who are doing all these things?" she would ask emphatically, then go into something about antecedents.
"It's Raining, It's Pouring,"
Word Ways: Vol. 25
, Article 15.
Available at: http://digitalcommons.butler.edu/wordways/vol25/iss4/15