I can't believe the police took the Tanner sighting serious at all. 5 years wasted. Pull the other one. Abduction can also be ruled out in the Smithman sighting IMO because no abductor would be crazy enough to sneak into an apartment and walk of with a child in their arms through the streets for everyone to see. Pre-planned abduction with all the comings and goings that night. Suicidal more like.
This is the big practical problem we have now.
If bundleman could be ruled out at the drop of a hat, Smithman could easily be found to be some kind of red herring. Then what?
It may even be the case that information about Smithman does exist somewhere, and has been overlooked, like much of the material in the early investigation. Who's to say that SY won't uncover old information on him as apparently they did with bundleman?
But the main problem for SY with regard to Smithman is that he contradicts their current position that Madeleine's disappearance bears the hallmarks of a professional abduction, involving reconnaissance and a team of people. The professional team aspect is the one thing that SY have been explicit about with relation to their current search.
There is absolutely nothing professional, however, about Smithman's MO.