I think it's right to take accusations of this nature seriously. For health reasons especially. Judging by your posts, on this topic, you do as well.
Yes Matrix, I take health very seriously and will warn others here if I suspect a girl of having STDs/STIs. Same applies to where I have a bad experience with a girl who doesn't offer a good service, I warn others in here.
I have thought a bit more about your above comments and did some more Google search, apparently Gonorrhea is the most common form of STD/STI and the symptoms could show within two days of getting infected, it could also take a couple of weeks so it varies, and discharging and pain are the signs. But you are right the likes of HIV could take six months to show not two days. Gonorrhea could also go unnoticed in half the women which means the condition can go untreated for some time, the ratio in men is 1 in 10. So this Fionka might not have been aware she had an STD (or STDs if she has more than one), and once reported by a punter on AW she hid her feedbacks. Based on what I have read on NHS web site other diseases take more than two days to show, but not Gonorrhea.
I am also puzzled how Eastern European girls who are touring cities in the UK can get medical help, they will not be able to register with GPs since they would need proof of address and identification, since these girls like Fionka move around they won't have such evidence to register with a GP.
So they would need to go to hospital or a clinic, but again Hospitals and clinics ask for identification, address and details of GP. The likes of Fionka might choose not to get treatment while they are here and deal with it when they return home. Clinics and Hospitals would find out this girl with a Polish accent and no permanent address in the UK is most probably a prostitute. I am not sure how the NHS deal with such cases (EE prostitutes) but the girls themselves will be reluctant to own up what they do here and how they got their infection/disease.
Just a thought but I don't know how the likes of Fionka get treatment in the UK.