Hi,
Personally for me if I am seeing someone outside of escorting it is because they are something damn special and more than a fuck buddy. Therefore, I would feel the need to be clear from day one. Yes, I would run the risk of it coming out, but I just could not keep such a secret as I'd leave the person instantly if it were me. Not because of their job, just lies.
But that is just my opinion and YOU are the one that sets YOUR moral compass, be damned with anyone else's opinion.
I agree though, that the cash element is irrelevant.