Run my own business, and wouldn't have the courage to do it. Bookkeeper and accountant regularly go through my books and often ask what various expenses are - while they accept most any answer, I'd still be scared. For example, I could say that it is a "coaching session", training or whatever. I would have to ensure that that the SP used a "discrete" and appropriate billing name, as opposed to something like "Screw My A** Consulting Group."
If I did this, I would ask the agency to write-up a receipt, but if they were not used to doing this, I would "fake one" of my own to support the credit card transaction. Of course doing this is highly illegal, and if I were audited and caught, I would not only have to pay fines and penalties, it would be embarrassing to be caught for this reason.
Overall, I would rather not associate my business with my hobby in any way.