Not recommended IMO unless you have some pretty unique circumstances.This is why ADUs have been a big fail is SF.

If you fail to follow the rules, you may open your personal assets to a lawsuit.

Thanks Jay,I guess the question becomes following @Chris Seveney's comment, which of the two would have a higher weighting in your opinion.

Another great tool is to incorporate a quality home warranty (paid for either or both parties) to alleviate some concerns about items that are functioning but not failed. 

they will be worth their weight in gold

If the other options fail, that allows you to keep the 3% and only pay the higher rate on the repair in the meantime.

Sellers go out thinking they have a deal and contract for their new living arrangements only to have their deal fail and now it puts them in a pickle.

Most try and fail.

To make a long, expensive story short, we discovered that builder failed to insulate an entire 3rd attic space and didn't seal wall cavities up in the main attic or insulate chases properly (Inspector failed too). 

Failing to claim expenses can lead to mortgage fraud or even major tax issues if you get certain refundable credits.Not worth my time to comment further.