This is the kind of "Alph-Male," talk that I hear often. Thank you for saying it.
This is extremely limited thinking for a 5K and even for a 3200.
We see lots of kids winning 8 straight meets during the regular season. Then at the state meet everyone thinks and says they have choked because they went out too hard and blew up. But it isn't that people go out harder at the state meet. It's just that you have more good runners than in regular season meets. You have the best of the best there.
There are of course a few newbies that go out too hard at state. But here is where the coaching comes in---you must teach them that many will come back to them if they are patient early. That does not mean that you do not run with the people you should run with...but you can keep them at a distance and gradually pull them back in. (I'm not sure you understand this principle as the entire field might be running the race wrong. In a 5K a smart kid can come back with the right plan but it's a hard sell.)
But it's hard for coaches to teach that, especially if the girl or boy has been blowing out the field every race. I wish I had the secret to teaching that and that is the purpose of asking the question.
(Getting faster times during the regular season is best done by going out hard if you do not care about winning. But what happens to the kid's mind if you do that every race and his times or placements do not improve? You better be a great coach if you want to pull that off. You do not beat people who are better than you by trying to insert a quick 400 meters at an early phase in the race!)
It is also easy to get kids to go out hard. That is a natural inclination for most kids. It's also foolish and you will lose many good runners that way.
For some kids running a 5:55 mile is not going out hard. It's going out at the pace they should be running. It's not hard for them! In addition what if the first mile is downhill? Fast is relative to who is running. Above all I want my kids to run smart. One can be in incredible shape and ruin their race in the first 100 meters. I could tell you some stories about that one!!!