There are some claims that Luke didn't return home after school, because he went straight to the woodlands strip to "wait" for Jodi. There are several problems with this theory (not least the witnesses who saw him walking his usual route home).
Firstly, either he would have had to be carrying the weapon with which Jodi was killed throughout his day at school, or he had "stashed" it somewhere in advance. It was never the prosecution stance that the murder had been pre-planned - their approach was that a fight had spontaneously erupted when Jodi allegedly confronted Luke about another girl. From all of the forensic and pathology evidence available, the knife used to murder and mutialate Jodi was a large knife - where did Luke "conceal" such a knife on his person throughout the school day?
The claimed spontaneous fight came about because, the prosecution claimed (without a scrap of evidence), Jodi had found out at lunchtime about another girl. So, staying with the "he didn't go home after school, he went straight to the woodland strip" theory, Luke had no reason to leave the house that morning carrying a large, concealed knife. He didn't go home at lunchtime, so when did he acquire the knife in order to take it straight to the woodland strip after school?
Then there's the point you make, marty - if the ungrounding that day story is true, Luke would then be waiting in a woodland strip for someone who wasn't going to be out of her house that evening.
Next, there's the curious question of why he would have come out of "hiding" to put himself in full view at the Easthouses entrance to the path (as per the Bryson sighting) - why didn't he just wait at the junction of the paths until Jodi happened along there? If he'd hidden for over an hour, why choose to come out of hiding at all... and what a coincidence that he came out of hiding to be at the entrance to the path in the one minute window available to Andrina Bryson to make her sighting!!
(For clarity, the Bryson sighting was timed at 4.49 - 4.54. It could not have been 4.49, because Jodi did not leave her home until 4.50. It could not have been prior to 4.52:40, because the walk from Jodi's house to the Easthouses entrance to the path was timed at 2 minutes and 40 seconds, so there is just 1 minute 20 seconds for the Byrson sighting to have happened, accccording to the official timings.)
And we still have the mystery of the landline making an outbound call at around 4.15pm, and a dinner that cooked itself by 5.15pm