Regulus had been prepared to lie if needed. He wasn't above doing it, even if they were Sirius and James. In fact, he didn't think that absolutes meant much. Never lie was just another absolute that he didn't have to pay attention to, but then Remus explained, even if not in an obvious manner.
"I picked colours that we would all see, especially the child of the house, who playing with the decorations," he added, very calmly, and daring anyone to say anything further on the subject.