Importance of information Sessions/Happy Hours

If you choose not to attend, it won't be the reason you wouldn't get a spot. However, just think about it from a supply and demand POV - the more you go to these kinds of things, the more actual face time you get with junior management and the more holistic your application will be. At the end of the day, the deciding factor in being offered a role will primarily be your performance within your firm, but it gives folks like us who do the hiring a better picture of who you are if you attend. 

I'm going through this process right now on the other side, and we've had a couple of 'optional' sessions for pre-cycle recruitment. By going to these, I can get a better sense of who I'm talking to before they step foot in the interview room in a couple of weeks. If I see that candidate A's performance may have been a couple of points below candidate B's factorials, but candidate A took the strong initiative to take an interest in getting us to know better, I may go for candidate A. 

At the end of the day, you're your own PR firm. You can choose to capitalize on your skills however you see fit, but I'd highly recommend you hit every information session, informal event, and get-together that's offered - provided it doesn't affect your banking performance. It's those small things that can really drop the ball the right way when it comes down to punch timing offers. Best of luck to you.