I'm actually on your side on this Brietta.
IMO it's obvious the smith sighting was not of GM and was not of MM.
Very obvious because the man they saw was wearing white or cream trousers, and the girl they saw was wearing long sleeved top.
The sighting has nothing to do with the case IMO.
The Smith sighting has gained the notoriety it has because of a very nebulous connection made to Madeleine's father.
The Amaral investigation gave it little weight or attention as far as the missing child herself was concerned; the Rebelo investigation gave it no weight as far as the investigation into the 'prime suspect' was concerned.
Just another coincidence of this sighting is that Murat, who had just been made an arguido was definitely 'ruled out' by Mr Smith; while McCann, who had just been made an arguido was nebulously 'ruled in'.
Both statements were made while Amaral was co-ordinator of the case ... which raises interesting speculation as to what might have been made of Mr Smith and the event which "triggered" the addition to his statement and "showing his full availability to travel to Portugal with the aim of making statements and collaborating with this police in all the diligences that could be considered necessary concerning these events."
Paiva if Amaral had not been sacked and someone who could see further than the end of his nose appointed in his stead.
Whether or not Martin Smith has changed his opinion is a total irrelevance.
The people who matter have concentrated on the original alleged sighting by a family of nine; three of whom have statements in the public domain.