How many McDonald's workers were there ? Or was it mostly bandwagon hoppers out for a day of rent-a-protest ?
On the grand scale of thing, how much impact did you make ? 13000+ stores worldwide, and you picketed, what, eight, ten ?
We're sure that the majority of customers were too hungry to turn back at the sight of the pickets, and probably couldn't give a shit whether the person selling them their Big Mac Meal is in a union or not.
If you want unions in, don't hassle the customers ! SELL the idea to the crew. It's not the public you have to convince after all.
It wouldn't, by any chance, have been shameless self publicity for the IWW ? If you want to work for workers rights do something constructive. Getting the attention of a few people who don't give a toss for a nano second isn't going to help the poor downtrodden workers is it ? We don't see the outraged public queuing up to stick their necks out on behalf of the crew.
Get in touch with the crew who work in the stores. Convince them why it's right for them. Help them to unionise instead of riding on the tail end of a protest. Be proactive, even if it is a bit too low profile for all you glory seeking champions of workers rights. Stop waving your flags and banners and work a bit smarter. Then you might see some results.