Even at Google connections matter!
You don't NEED to do anything, it just depends on what you're trying to accomplish. If you are trying to get an advantage with regards to your career, then the answer is "Yes, you do need to attend networking events." Quite recently I found myself at a company party for Google and I was talking to some of the employees. I was talking to one of the people who worked as an engineer for Google and it went like this:
Me : How did you get hired? I've heard it's a pretty tough process. You must have impressed them a lot.
Google Engineer Guy : My girlfriend is really good friends with a manager there and she got me an interview.
Even at Google and even for a position such as engineer where one would assume it's purely about your skills - connections matter!
You can definitely get a really good job by grinding it out, having an excel sheet of all your applications and just grind it out. It's possible, however for every single application you are sending out you are entering a MASSIVE funnel with literally thousands of other applicants. A friend of mine is a system's engineer for the world's largest recruitment firm - Adecco. They were advertising a marketing internship position and he said in 24 hours, they received more than 4,000 applications. What are the chances that you will get the job and not the other 3,999 people? The odds are stacked against you and networking is one powerful tool you can use to improve your chances.
Networking is a must if you want to simplify your job seeking efforts
Having said that, it's important to network effectively and pick the right networking events. A career fair sounds like a good idea, but the people at the PwC stand are alumni of your university with no power over recruitment. They can be useful in terms of offering you advice on how to improve your application however no matter how much you show them you're a "team player" they don't pull the trigger on your application. You mainly want to aim for events where a high level executive will give a talk and then there will be a networking event afterward. Use LinkedIn a lot, track down the people who deal with campus recruitment, get on their radar and they might help. In sum, networking is a must if you want to simplify your job seeking efforts. I also want to add that in the end you have to put in the work, that Google engineer didn't just get hired because his girlfriend was pals with the boss - he was quite smart too.