Someone warned him but he was also checking submissions offscreen prior to that anyways and he's even brought up the fact in the past that he's had to be careful with checking his and others' twitter feeds due to people posting porn or other crazy shit they retweet or the people he or they're following post. Point is that he was actually conscious of it and made an effort, even with the advance warning from the viewers he was still doing something about it just in case. Swifty clearly didn't and wasn't.