Not sure how often this happens. Here's the story:
My MIL had been getting quotes to have her furnace and A/C replaced. I had been educating her and really, helping to educate some of the local contractors on how the tax credits work. She was pretty well settled on a particular contractor and a 80k BTU Carrier Infinity 96 furnace with a 2.5 Ton Performance 15 A/C.
She hadn't finalized anything or scheduled installation, but she gets confused easily. Her and her husband don't always communicate well either.
On Monday, another contractors comes to her home and says he's here to replace her system. She figured... well maybe they are subcontracted or something. So she lets them in and they get started. They have the furnace torn out completely and are unpacking the new condenser when my MIL notices it seems like a really large unit. After a few calls... it's realized that they had the wrong address. The client was the previous owners of the home, but they send the installer to the old address.
I figure about 1/3 my MIL's fault for letting them start work when she hadn't even scheduled it and didn't follow-up with the main office. The rest is the fault of the contractor for mixing up the addresses. SHe hadn't even gotten quotes from this company.
So the contractor puts them up in a hotel for the night and installs a temporary air handler to get them A/C for the time being.
Ultimately they are offering her an Infinity ICS furnace and Infinity 21 A/C for almost the same price as her other quote. Based on the details in the quote, I get the impression they may be the closest thing we have the a professional installer (quote actually lists testing the static pressure, flow, temperature and replacing the return and supply plenum). Other line items are very detailed. All other quotes I've seen around here were very vauge. My MIL also said they seemed very professional... for what that's worth.
I give them a big thumbs up for making it right and offering her a sizeable discount on the system. Can't blame the installer. He has an address on his work order, and the owner let them in. I suppose he could have verified the name on the order.