Because they were the main protagonists in the "train" ?
"The best solutions are often the most difficult to find, not
because they are hiding but because we don’t bother to look for them".
Sorry, I still don't get it.
You can use a stopwatch to observe the T9 re-enacting arriving at the Tapas restaurant and going back and forth over the course of the evening.
How are the T9 suppoed to remember how fast they were walking at the time? Not just a year later, but even later for all those who insist that a "reconstruction" would have reopened the case years later?
And a "reconstruction" timeline without any of the other witnesses, e.g., Tapas staff or other holidaymakers? How does that work?
What makes sense to me (although possibly not to others) is to see if the sequence makes sense and to establish whether there were indeed windows of opportunity for an abductor to have nipped in and out without anyone noticing. There were, but the timeline would never be able to narrow it down to a specific short gap given that people on holiday weren't using a stopwatch at the time. I don't see how a physical or virtual reconstruction would resolve that to within a couple of minutes.
If there had been NO windows of opportunity, then there would be some serious questions to answer.