Colleges also put pressure on companies by starting the recruitment process 6 to 9 months before a student graduates. This way, students settle for sub-optimal jobs, and good companies lose out because they are not volume recruiters.
I faced this in 2004 while doing campus recruitment at one of the leading datacom companies. We were the 4th company on a particular campus in TN (TCS, Infosys and Cognizant were there before us and each of them had made 200+ offers), but couldn't get many students to sit for the process as they were already placed. There were some bright students at PSG etc in Coimbatore that were waiting for companies like ours, and not following the herd. But we drew a blank at all the NITs, and didn't even go to the IITs because there were hardly any students left to recruit.
IMHO, campus interviews should start closer to the graduation time, preferably after the GATE and MBA admission interviews. This will allow both the students and the companies to prepare better for the recruitment process.