Why are people STILL trying to hire illegal part time maids??

We've had an absolutely lovely live in with us since May. She's been just fantastic, can't fault her at all. She doesn't ask anything of us, we've never once gotten the sense that she wants to take advantage of us in any way, even with legitimate stuff (her mother even passed away just before she came to be with us and she didn't even tell us, didn't ask to go home, etc...) She's very respectful and I adore her.
Tonight she came to me and said that a friend's madam has a friend in Arabian Ranches who wants her to do part time work for her 3 times a week during her break time. (so that would mean in the middle of the day or on Fridays as she usually has a break during the week for about 3 hours around noon or so). I explained to her that it was illegal and that the police were cracking down on this lately and she could go to jail and then be sent back to Ethiopia and we could have a very serious fine and get in trouble also for letting her. I told her that this madam should know that if she wants a part time helper that she must go through an agency.
My helper was respectful about it - She thanked me and left the room. I am pretty sure she understood even though she was disappointed (although her English isn't too fantastic so I often worry that something as important as this may get lost in translation)..I know she's really disappointed and would love the extra money. I hear her in her room right now having a conversation on her mobile and she sounds upset, almost like someone is angry at her. I feel sick to my stomach, because I'm so worried about how this will affect her. She has to watch these other helpers make extra money in their free time, and see so many "madams" hire them without a second thought! I am worried her satisfaction with us will now suffer as a result.
I truly believe she did not go looking for the extra work, and she did know enough to come ask me for permission first...so she must have been aware that there could be trouble, I suppose - it's like one of those calculated risks...you see so many people breaking the rules, it's hard not to assume that the risk is very low compared to possible reward, otherwise so many people wouldn't be doing it, right? THis just infuriates me, because now we have a bit of an 'elephant' in the room.
Why oh WHY are some ladies STILL trying to hire part time maids without going through an agency??!! There is a trickle down effect to your actions...It actually breaks my heart to have to say no to her. She's such a great worker, and I'd love to see her be able to legally make more money. But as an expat, you'd really have to be living under a rock lately not to know that this is illegal!

OK, that got kind of long...sorry. Had no one to bounce this off of right now and I just feel sick about it.