After Charlotte's breakfast, the lady instructed Louis to wear her scarf not because she knew first that he was wearing it but because he seemed to forget it from the guest room.
Charlotte couldn't help but feel as if she was teasing Louis from the way she said those words, and it's because Louis' face was red
It's not anything of anger or hate but because of embarrassment - however, not in the wrong way. It's because after the last said that Louis should wear his scarf, he remembered what they had done in one of the guest's rooms. Just by reminiscing what they had done earlier, Louis couldn't help but put the back of his hand to his lips while trying to avert his sight if the teasing lady
Well, since no one was within the hall where they were, Charlotte thought she could tease Louis even more, so she did