Those who pay for her services see a record of purchasing a consulting service on their credit card. Though this seems clever, she will technically have PII data on all of her customers if she is somehow caught in the future, but the chances of someone like her being caught may be smaller than most.
I guess they could do prepaid CC's, but still the prostitute would have to be pretty geeky to want to deal with the hassles involved. Do those prepaid CC's work for everything? I tried to use one to make online purchases once and it wouldn't work.