Ex-D1 P5 wrote:
Because they would also show up on relevant D1 performance lists, NCAA regional/preliminary meets, and at NCAAs. I never saw any non-D1 singlets in my races at Drake, Texas Relays, Sun Angel, Stanford, and the rest. I rarely raced in the early season rust busters where lower tier D1 athletes went for conference meet seed marks. If you ran at a D3 program against D1 guys they had to have been from directional schools, minor private schools, and alphabet state schools.
Well perhaps you are not all that observant. I ran D3 and at Drake, and my team did three of the four years I was there. We had teams entered in the college 4X100, 4X 400, 4X800 and DMR, and in the university 4X 1600. The latter against all the D1 teams, former against D3 and D2 (and some of those D2 teams would compete well against D1)--e.g., 7:20s for 4X8, 9:40s-50s for the DMR. D3 were usually a notch lower, but often they'd stick their best guy in the 1st leg of the 4X1600. One year my friend (didn't know him at the time), lead the 1st leg, handing off in 4:04.
I'm older now, but my kid ran D2, and ran in some large west coast D1 XC invites, and there were several D2 and D3 schools in those meets.