In this case I would suggest creating a "sucks" website for the company in question to shame them. It has been upheld by the court system as a 100% legal thing to do... (for examples see paypalsucks.com and riaasucks.com)
This is a very bad advice for a number of reasons.
As others pointed out any sort of quirky publicity stunts will only complicate matters for the designer should the case (in whatever form) end up in court.
As others pointed out any sort of quirky publicity stunts will only complicate matters for the designer should the case (in whatever form) end up in court.