Wis. Stat. § 452.139(2)(a) attempts to answer this very question:
A client is not liable for a misrepresentation made in connection with the provision of brokerage services by a firm or any licensee associated with the firm, unless the client knows or should have known of the misrepresentation or the firm or licensee is repeating a misrepresentation made by the client.
At first blush, this statute appears to absolve sellers from liability from most real estate agent misrepresentations. Trouble is, the standard WB-1 Residential Listing Contract includes provisions under which sellers specifically authorize their real estate agent to market the property using certain media and to "do those acts reasonably necessary to effect a sale. . . ." One could use this language to argue that the sellers should have known of their agent's misrepresentations because they specifically authorized - and even demanded - that their agent advertise their home a certain way.
In order to reduce this risk, I recommend that sellers demand that their listing contract include a provision giving them the right to approve or disapprove the content of all advertising prior to its publication.
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