Seems fairly unethical. But as a calculated risk I cannot say that I would reject it out-of-hand. $15k worth of education isn't worth a whole lot these days, and win, lose, or draw, such an adventure would likely prove to have some educational value in and of itself.
Besides, it should be possible to pay off the $15k going forward if you lose. It's only one less cheap car. It's been a _long_ time since I was involved with student loans, but it strikes me that you might want to be careful about ending up with a criminal record for fraud. Also, you might need to win fairly big to account for the tax implications though that strikes me as quite possible (as does losing it all.)
If this is considered fraud I won't be doing it, I will be doing more research about that. I have a credit card, but 30% interest is a bitch...
As for the taxes, if I actually did win big I would hire an accountant and a lawyer. I don't want to fun afoul of the law, that is the last thing I need.