Exactly he could have been anywhere.
There's no one who suggest's he was there,Tannerman looks nothing like him,Mr Smith has according to press reports claimed he's nothing like the guy who was carrying a girl (fitting a description to that of Madeleine),last bit attributed to Redwood.One child and one man unaccounted for,Smithman and Madeleine,find the first imo and it'll lead to the second.
There are eye witnesses who gave statements to the effect that they became aware of a man or two men who attracted their attention because of the intensity with which they appeared to be surveilling the McCann apartment.
It would only take one or two of these to have identified Brueckner with a certainty of 99% for that fact to become evidence.
Before you scoff ~ please take time to consider that the McCluskey and Smith 'identification' of the mediatised Gerry McCann (both of which were
proved wrong by the Judicial police at the time) is accepted by an exceedingly high percentage of sceptics as one of their main planks of 'evidence' justifying their 'suspicions' etc.
Also think on before you scoff at Brueckner's phone ping in Luz just prior to Madeleine's disappearance ringing warning bells for today's investigators.
Consider the unrelenting feeding frenzy sceptics have had over McCann phones and phone traffic from the length and breadth of internet sceptic fora.
Only yesterday a member of this forum raised the issue of McCann phones being cleared after Madeleine disappeared. Of course they were cleared 💥
Back in 2007 when a phone message in box was full messages had to be cleared before new ones could be received. It is not a great mystery the explanation is as simple as that.