OR.... he is completely, totally, 100% confident because he knows with a sure certainty that they are elsewhere....
True, that could be another possibility, even if a hunch of his, he seems so certain.
I think there's a whole constellation of reasons why he could be so certain.... but it seems like he wants people to know there is nothing "sus" on his property based on his searches and he did a good job, and if he says "they are not here anywhere, I checked and I would know!!" it heads off speculation, could be one reason.
MBM was with the toddler in bed and he could have yelled at the kids to be quiet, unbarred the door that was barred to keep bears out (?), went back to bed, and been half awake when he heard noises way off in the distance, and was too out of it/half asleep/nodding off cuz the kids were finally quiet, and so tired from staying up late working on the fence and working a graveyard shift earlier in that week IIRC, he was just too zonked out to be paying attention -- while inside before they realized it had gone quiet and they were gone.
While outside searching after they vanished, I think that's what he is so surefire about having checked everywhere. But he could have been yelling for them and frantic or mad "they had wandered off''
without waking up their parents to tell them, which could have been distracting in terms of doing a very thorough search, but he said so just the same.
In terms of "not telling their parents" or sneaking out, I don't think I've considered much before whether there could have been someone who came to the door/peeked in or they saw out the window or when they opened the door to see what it was like out after breakfast, and they were quiet making "shush" signs, as in "shhh, don't wake mom & dad & baby..."
Could someone have motioned them over or asked them to come out to play, or had a box of donuts or a new kind of candy or a toy, or a bunny or a puppy, or something / anything appealing to little kids....
And they followed that person or decided to walk into town on their own to get some goodies too?
Or walk to the bus stop, not knowing it wouldn't always be there at more than one time in the morning for pickup, like in the city where they come all the time?
Or they knew the bus came back from dropping the kids off at school in the morning going the opposite way some time later to go back to the bus yard, and were hoping to see them coming back and going in the opposite direction at the time a bit later in the morning, and went running out to wave hi or try to "catch the bus?
These types of scenarios could fit if:
(a) They knew the bus route and when it would typically pass by after school drop off going back where it started from, and In some rural areas the bus company lets the driver take the bus, if a smaller one or a "jitney" as they call them there, home with them, so the route back could have been out that way / in their neighborhood and not all the way back into town. So when they were "home sick" and bored, they could have wanted to wave hi as it went by back the other way.
(b) They knew people/other kids who came around now and again who might have been visiting the neighbors or DM's mother or brother, all on the same property, or was a regular delivery person, or someone in the area, who if they missed the bus on other occasions and would have said hi to them and aww shucks, you missed the bus? You're not in school today? You going back home? And then went on about their business being used to seeing them around.
I don't think them "going outside for a reason" and then getting distracted and then getting lost has been ruled out by LE.
Just upthread last week I posted a link to an MSM article from June that said
LE will not disclose if Lilly and Jack had contact with anyone else in the days leading up to (or on the day of) their disappearance.
As in, it didn't have to be an abduction right off the property as LE has said there is no evidence of (under their sleeping parent's noses / out of earshot), but a "luring off" of them, which started innocently, if they were bored at having to be quiet and then got excited about something, went outside, and got lost
DM said he thought he heard a scream after LE started searching, but it was drowned out by helicopters.
So that would have been within one to a few hours of them going outside and "wandering" unbeknownst to their parents.
And with their small kid-sized gaits, they would not have made it very far if walking in that amount of time, so could have been close enough if it was them that DM could hear them or Lilly screaming.
If he did think he heard screaming, even if drowned out, I assume he told LE, and they looked into it somehow.
All "coulds" and IMO.