The reporting on that story has been really bad. The woman and the man ended up in arbitration. The panel decided 5.2 million was fair compensation. They also added a stipulation that the guy had limited liability and she needed to collect the judgment, if possible, from GEICO. GEICO did say, 'Whoa, wait, what??!' and asked to have the amount reviewed/overturned/give them a chance to defend.
The court ruled that they could have helped defend the man, their client, at the arbitration hearing, and did not. Due to the court's limited ability to overturn an arbitration award, GEICO was told no. They aren't allowed to have another arbitration hearing to change the amount.
What the reporting leaves out is that there is a second suit pending that will determine whether or not getting and STD in someone's car is something covered under an auto or umbrella policy. That will almost certainly go in GEICO's favor, because it's just stupid, and the woman will not be able to collect a damn thing.