I don't think non-academy clubs will bid early on academy players. They would have to actually be willing to give up that selection if the team whose academy it is doesn't match the bid. So big risk to try to make them pay overs if it means you could end up with a player that isn't as good as others you could have chosen at the same pick.
In a lot of cases it won't be much of a risk. Let's say Carlton bid for Callum Mills at pick one. Sydney has to match the pick because if they don't they get pick 33 and a bunch of other later second, third and fourth round picks. They also get a 25% discount so they are not in effect bidding Pick one points. They are essentially deciding on getting Callum Mills, the best midfielder in the draft or 5 or 6 late picks, 4 or 5 of which will probably never play more than 10 games.
If the inexplicable happens and they don't bid for Mills then Carlton end up with Mills who could well end up being better than Weitering anyway.
It's a no brainer and I hope it happens.
There are similar examples for GWS and Brisbane - they have all declared there hands by drafting all their good picks away (Brisbane pick's 2 the exception) to get meaningless picks down the order.
GWS and Brisbane could get smashed if Carlton or Melb decide to bid on all their top 15 rated academy kids at pick 1 and 3..