This is true. Following the coaches on twitter it was eye-opening how every time a coach tweeted something, they'd get 5-10 replies from players saying, "Hey coach, check out my film," with their hudl link, etc. It was kind of sad. It made me glad I'm not a coach, it'd break my heart if I had to tell 3,000 kids, "Thank you, but no thank you." (Which they didn't, they just didn't respond.)
And @John Wardthat's also partly the player's high school coache's job. If the coach truly thinks the kid can play he should contact the college coach. But the coach can't be blowing smoke at the college coach or they'll lose credibility for future player recommendations.