Didn't North only realise Sanders was eligible for NGA late this year, and tried to retrospectively add him despite having nothing to do with his development?

If they had to be signed up by the time they were 15 or 16, would that help?

The other thought I had was around points...
If a player is bid in the top 10, then you need 1x top 10 or 2x top 20 to match it.
Bid in top 20, 1x top 20 or 2x top 30.
Etc

One of the biggest rorts is the ability to match a bid at #2 with 6 picks in the 30s.