Um I worked at Manpower as a recruiter, and whilst I can't speak for San Jose I can say we told people that it's customary to be 10-15 minutes early for work. I was at work before my shift daily as "hardnosedmanagertype" said. And while I do think he/she was harsh, they are correct that X/Y are lazy. I am Gen X, and I find my similarly aged colleagues have a different opinion of good work ethic.
I don't think you need to be "working" unpaid 15 minutes early, but everyone should be at their station a minimum of 5 minutes ahead to yes, turn on their computer and start logging in. Be realistic. What's that 5 minutes? You're telling me you don't waste 5 minutes of the company's time during the day? How about if they dock you for internet surfing you inevitably do? Or that five minute goof off chat at the water cooler? Yeah so grow up.