request for free legal work

I am a lawyer in sole practice.

It's Friday afternoon, and I have just received email from an acquaintance in which he requests that I promptly review a 19-page contract for his wife, and give him my "quick, nothing formal" comments. He also informs me in his email what in particular are the provisions in the contract that she is concerned about. He further informs me that she needs this by Monday. He also mentions that they would be happy to take me to lunch or dinner to compensate me for my time and efforts.

I have been practicing law for approximately 20 years in a large urban setting. I charge $350/hour which is a very common hourly rate here, not very expensive. In my experience, it takes a few or several hours to review a contract of this length, discuss it with a client, prepare the redrafts, have client review those and then finalize it all. It also very common that I will later receive additional, follow-up questions or requests as the contract is being negotiated with the other party.

I generally eat salad for lunch or dinner, a $20 fare even at the most expensive restaurants.

This is certainly not the first time that I have received such a request, and a similar offer of a "compensation", if any at all, from a friend or acquaintance.

How do I politely tell them that their request is inappropriate on all counts, including the time constrains and lack of consideration for my professional responsibility and compensation?

"AmazedAfterAllTheseYears"