Seems like refusing to tip only hurts the people who have no power to change the system (and less savings to survive it than the bosses). We need to affect the business owners not their employees. Refusing to eat at restaurants who don't pay their workers a living wage would be more effective, but it'd have to be coupled with lots of communication about why it's happening so it's not passed off as economic trends or something. Unfortunately in the US, there aren't really many/any non-tipping alternatives to give your business during the strike.
Legislative action, starting in a few smaller test locations, might be actually be more effective at this one.