Most people bath in the shower or bath. Blood wasn't found in the shower. She didn't walk on the bathroom (or corridor) floor either. She did the 'bath mat boogie', remember?
The samples were tiny...hence why no DNA could be extracted from some and only LCN values from the others.
Did any of the defence experts or lawyers make the argument you are making?
I don't believe they did in the first trial because they were not told about the TMB test. Hence, why I was talking about failure to provide evidence. I think they learned of the negative TMB test during trial and thought they then had a simple explanation of why the evidence should be thrown out.
You had asked someone else earlier if they thought the defense was incompetent. I do think the defense team is incompetent.
The shower typically would only show evidence of blood within the drain since the shower surface is non-porous (this according to my CSI evidence collection friend). Typically a bloody footprint trail on a porous floor would dilute in strength as the residue is transferred from the foot to the floor. The prints would gradually dim as more residue is transferred, which was not shown by the photographs or claimed by the testers. Instead, the footprints retain cohesion, implying a high amount of substance on the foot. Yet there can't be a high amount of blood because the TMB test was negative.
The science isn't fitting with the theory of blood.
Now, if the prints had been wiped up, that would be something, but there are no smear marks, which means they weren't wiped up.
As for why there was no other evidence of anyone else, the roommates claimed the entire flat had been cleaned less than a week prior, that side of the house was used primarly by Amanda and Meredith, and so you should only see evidence of activity after that cleaning.
However, I do think that the footprint on the bathmat was a bloody footprint (though I don't think you can claim certainty as to who it is, especially if you are saying stomach content science is soft... footprint science is even softer) , and the only flourescing footprints I know of are Amanda's. I am not providing excuses for Sollecito's footprint showing up anywhere.