A bit late in the game here... but if the windshield has been replaced it was probably not sealed correctly (seen it before, once on a new vehicle from the factory).
As for [MENTION=136088]Fubar22[/MENTION] it's been stated already that "Toxic Black Mold" is not an entirely realistic phenomenon as presented by you and others in the past.
Does Stachybotrys chartarum (Stachybotrys atra) cause acute idiopathic pulmonary hemorrhage among infants?
To date, a possible association between acute idiopathic pulmonary hemorrhage among infants and Stachybotrys chartarum (Stachybotrys atra) has not been proved. Further studies are needed to determine what causes acute idiopathic hemorrhage.
The above is cited from the CDC's own page:
CDC - Mold - General Information: Facts about Stachybotrys chartarum and Other Molds
That's not to say that Mold itself isn't harmful to human health; those who have Asthma and/or allergies may be susceptible to illness due to mold spore and those who aren't can also develop upper respiratory symptoms. Though most cases are easily treatable and non-lethal.
Additionally once the source of the mold is taken care (i.e. conditions allowing mold to prosper) the mold will typically dry out an die off. Bleach can also be used to kill the mold; so "cleaning" the vehicle would probably have been a perfectly fine repair. The only issue is that they would have to tear apart the entire vehicle and possibly either professionally clean the cloth and/or replace it; which is probably why they bought it back because it wasn't worth the rental vehicle costs to do so (not to mention what I can only assume is your generally rude attitude to those who contradict your pre-established beliefs; at least based off evidence in this thread.)
To be fair I was about to jump in and lambaste those disagreeing with you because of how dangerous "Toxic Black Mold" was always presented to me; but after researching it further, I'm a bit embarrassed I did not do so earlier in life.