To be fair, everyone in camp always seems to know everything. What bothers me most about Halsin's flags is, that if you turn him down politely during his proposition, he insists that you have asked about his past lovers, even if you haven't touched that dialogue branch at all. It would be great if you could just shut down the conversation with a polite "I am flattered but not interested." if you have not inquired about his past lovers before. Currently, he only way to shut the conversation down in one step is the extremely rude one.