Yes, William may well have been carried by someone as they escaped on foot from either Benaroon Drive proper or after the right turn that leads to the forest and cemetery tracks.
I think the most likely scenario is by car. I have been thinking about this from the POV of police, prosecutors and defence lawyers.
There have been four cars described as being ‘of interest’ to the investigation in MSM. The (green?) sedan that turned into and reversed out of the neighbour’s driveway next to FGM’s former residence at around 9am. The (green-gray?) sedan and the white station wagon seen across the road earlier that morning; both reported by FM, and the (pewter?) 4WD seen speeding in Kendall streets around the time William disappeared. (Excuse me if I have the colours muddled up and please correct me if I do).
Now let’s say you arrest a suspect that doesn’t have a car that matches any of the descriptions given of cars ‘of interest’ and you go to trial. The first thing the defence lawyer will seize on is that the four cars above belong to someone else who committed the crime their client is accused of. There is reasonable doubt. Unless, of course, those four cars have been eliminated from the investigation.
I think the four cars matching the descriptions (or as close to, given known inaccuracies in witness statements) of those published in MSM were in the vicinity of Kendall that morning. Either one, or all, or none, belong to the perpetrator(s); depending on which, if any, have been eliminated from the investigation.
As
@Hbayne said, a fair few posts ago now, those cars are, or were, important. In fact, DCI Jubelin stated this in response to a reporter’s question in his September presser:
(20:50) Reporter:
'What about, are the cars still of interest?'
(20:55) DCI Jubelin:
'We're still looking at the cars. From the last time we put the appeals out for the cars, we received a lot of information and that's a line of inquiry that we're following up. As I said, it is unusual for an active investigation to go into how we're approaching it but, because of the uniqueness of the investigation and the public’s interest, we prioritise our lines of inquiry.
So we'll have a person of interest and we'll focus on that person of interest, we'll focus on the cars and we've got lines of inquiry going all over the place. We've got our dedicated Strike Force but we've also got access to all other investigators across the state if we need them.'
(21:31) Reporter:
'There was a car seized, at one point, matching the description of the graphics that were put out there. Can you say that [unintelligible] been ruled out?'
(21:42) DCI Jubelin:
'I can only say it's been eliminated.'
Source:
https://www.youtube.com/watch?v=v2JoQlll9AE