The Elf guy in DA:O is probably the only character you can accidentally romance just because of how aggressively they wanted you to see the homo and how little difference there was between basic "being nice" and seducing. You almost had to not recruit him to avoid it.

Anders you could at least bully the shit out of the entire game (which would keep him from hitting on you at any point) because the Rivalry mechanic was one of the best parts of that game.