I don't think she's clueless. Riley knows, this for sure after hearing the conversation between Danny and Bonnie, which was recorded accidentally on her voice mail (S2E02 "There's Something Fitchy Going On").
In that episode she erased the message and then decides to ignore it for the next couple of seasons.

Riley is still infatuated with Ben, also confused about her feelings towards Danny, and in the end she will have to grow up and choose between her childhood fantasy crush and true love. She doesn't dare ask them directly what they feel for her, afraid for possible rejection and hurting their friendship.
Ben and Danny have a similar problem of not wanting to talk about their feelings.

So, the show will continue until someone confesses his or her love for the other.