What if there was a setting: "I only provide service for free" / "I accept payments for my service" in your profile? Such a setting could even be on a per-case

What if there was a setting: "I only provide service for free" / "I accept payments for my service" in your profile? Such a setting could even be on a per-case basis. Imagine if you helped someone for a good part of a day, and they were ready to return the favor in cash, and you were given the choice to accept or decline it.