Wow are they really that manipulatingly aware?
It might not be conscious. BotP talked about "coping mechanisms": when you encounter situations in your life, you naturally find that some forms of response work better than others, and you're therefore more likely to adopt these - often without thinking about it. This is possibly what's happening with Chris, although I'm still undecided about him at the moment.
In the case of Danielle, it looks much more deliberate. When you consider her very provocative photo shoots and what we know publicly about her "relationship" with Dexter, she really doesn't appear to be the fragile, innocent creature prone to crying that she is in the house. Even at this early stage. it's starting to look suspiciously like BB12 Alex all over again...