I have only thought of phoning the cops once, but did not, did a negative review and the person has gone for AW.
Advertised as a busty German in her mid-twenties, got to the door met by a anorexic girl look about 14 years, but could have just young looking, I walked but thought hard about phoning the cops. I could have been wrong about her age, she was a Gypo not German. Still feel a bit of guilt about not phoning, but she could just have been a young looking female.
The way some politicians go on you would think all working girls were trafficked, we know this is not true, but a small percentage must be. I think it is correct to contact the cops, just make sure you have a punting phone before you phone the cops.