@ebi, I agree that they are two consenting adults, but ask yourself, “Is it professional?” The answer is resoundingly no.
Would a lawyer sleep with a client? UNPROFESSIONAL. ILLEGAL IN MANY PLACES.
Would a doctor sleep with a patient? UNPROFESSIONAL. ILLEGAL IN MOST PLACES.
Would a professor sleep with a student? UNPROFESSIONAL. NOT ILLEGAL IN MANY CASES, BUT IT WILL GET YOU FIRED.
You don’t sleep with your clients if you’re a professional (unless you’re a prostitute). That’s the easiest thing to judge. Now, you could sleep with A CLIENT if they are, perhaps, somebody you’re already sleeping with. However, moving in on a client, especially when one is at your mercy in a compromising position is completely unprofessional in all professions. So yes, we can judge him.