It doesn't make me less suspicious but it doesn't make me more suspicious. Because I think after so long, and with WT being so little, and the environment and weather, it would make it extremely difficult to find anything now.
And I don't know if she was getting rid of a body, throwing away evidence or a distressed mum looking for her little boy.
If in time it turns out she did tell people about the drive on the day, then that would lessen my suspicions. But thats JMO, it may not arouse suspicion in you. Just like the washing on the line doesn't make me suspicious, neither does the 000 call. But the drive, yes.