I think the seeding according to your time, and having it noted with different colored caps is a pretty good idea.
As far as the validation, here in Spain, for 10k run races (10,000 people registered, sometimes more) you get seeded according to your expected time. The way to validate that time is that when you register, you have to bring proof of the time you say you can do. Its enough to print out the results list from the last race you participated in.
If youdont have that, or dont bring it to registration, you get seeded at the back. I think this could help a bit..
As far as the validation, here in Spain, for 10k run races (10,000 people registered, sometimes more) you get seeded according to your expected time. The way to validate that time is that when you register, you have to bring proof of the time you say you can do. Its enough to print out the results list from the last race you participated in.
If youdont have that, or dont bring it to registration, you get seeded at the back. I think this could help a bit..