What obligation or ethical reason does he have to keep underclassmen out of the mock draft? Sure, they haven't declared... but I'd say over 90% of the players that hear they'll be drafted in the first or second round probably come out. The Ohio State linebacker surprised the hell out of people when he stayed in school. It would be a worthless mock draft if he didn't include underclassmen.
Although fun to think about, these things are pretty worthless. Here's McShay's 2007 senior rankings post-draft:
1. Louisville QB Brian Brohm (Packers, second round)
2. USC OT Sam Baker (Falcons, first round)
3. LSU DT Glenn Dorsey (Chiefs, first round)
4. Michigan OT Jake Long (Dolphins, first round)
5. LSU WR Early Doucet (Cardinals, third round)
6. Georgia CB Paul Oliver*
7. Kentucky QB Andre Woodson (Giants, sixth round)
8. Texas WR Limas Sweed (Steelers, second round)
9. Michigan QB Chad Henne (Dolphins, second round)
10. Texas DT Frank Okam (Texans, fifth round)
* -- Oliver was declared academically ineligible last spring, entered the supplemental draft, and the Chargers used a fourth-round pick on him. He was inactive for every 2007 game.
If DeSean Jackson goes in the 2nd round, why would Percy Harvin go in the first round? It is interesting that he has the Titans picking ahead of the Texans.