IMHO if the buyer became interested in the home, aware of it's availabilty, via an avenue other than the Realtor's marketing, then it would appear that the waitress would be the "procurring cause".
However, you should know that just making an offer on a property is a lot different than getting it sold and closed. My personal experience that in most transactions there is something that comes up that you could clearly demonstrate to a client that the value of resolving the issue was less than the commission paid.
Areas that I would be concerned about include:
1. Is the buyer qualified? (meaning has a lender verified their income, credit score, down payment, etc.).
2. Is the buyer serious? (if the offer is accepted, will they close escrow or do they have other options).
3. Will they agree to a fair selling price (sometimes buyers, thinking they can go around the Realtor, whose job it is to protect your interests...meaning get the highest price for the home), try to low ball the seller thinking that the seller has no options.
4. If the sale is subject to inspections, and there are problems, how tough can you negotiate with this person. A good Realtor is an excellent negotiator, which is truly where we earn our money.
5. What if there is a problem with the financing? A sharp Realtor will try to have the buyer apply through at least one other lender as a back up. When escrows close late or fall out, almost half the time it is related to financing problems.
6. What if there are legal problems after the sale. Buyers that sue for lack of full disclosure are common. 70% of lawsuits filed are brought by buyers who feel they were defrauded by the seller. Realtors other job is to protect you from legal entanglements AFTER the sale closes.
Things to consider. Not to mention the fact, if you are facing foreclosure, a judge or a lender will look much more favorably on your desire to sell if you have a trained professional handling the transaction. IU know of a case where escrow was delayed, the sale date was approaching, the seller brought their Realtor to court and the judge issued a stay on the sale to allow escrow to close.