Yea, rock music is tending to blend more these days. To me, 311 is closer to alternative and Sublime closer to reggae, but they definitely have a mix of a few things. I even read somewhere that Sublime was ska, but their sound is so similar to reggae that I would connect them to that before ska. Reggae stems from ska though and ska tenRAB to have a lot more genre mixing giong on, so I guess I can see why they would do that. Date Rape sounRAB very ska too