Well, I think the point of a picket line is that you're not supposed to give the business your business. Similarly, picket lines are about unions. The Fred Phelps example makes no sense since they're not issuing a call for labor solidarity. Once the picket line formed, you pack your bags and leave, and you surely don't eat there, make phone calls, or anything else that generates revenue. (O' course, if you're sure that management will end up doing the housekeeping, etc. you could be sure to make life miserable in the tiny little ways hotel patrons have made life miserable for housekeeping staff for years. :)
So, you go out for breakfast, pack your bags before you do and leave. Or, if you need that cuppa joe before anything else is possible :), then go, come back, then and leave. Crossing at that point isn't about defying the call for solidarity. It's about getting your bags and leaving and doing what they've asked.
If it were me, I'd probably explain to someone in the line what I was doing. It would be very dispiriting to see yet another person cross the line without knowing why. I'd also give them every bit of support possible, letting them know you're on their side. In the hotel, I'd give management a piece of my mind, explaining I'll never do business with their chain again. In fact, I'd probably buy some posterboard and markers after breakfast elsewhere and cobble together an impromptu message of support. If I had time, I'd join in. When workers are in that position, they absolutely need that kind of support.
I find it hard to understand objections to the rule that you don't cross picket lines. It's really simple. This discussion followed on the heels of ChuckO claiming that he wouldn't support stupid decisions by unions. OK. But there's no need to exacerbate and antagonize by crossing a line. If you don't support them, then you talk with people involved. Crossing the line, for anything other than a health emergency, just seems needlessly confrontational.
In John Thornton's case, I can understand. OTOH, having been employed by these family operations for many years, I have to say that, in my experience, these are the most exploitative places around if you're not a family-member who stands to inherit the business. You don't need to cross the picket line. If you take issue with the union's decisions to picket, then talk to union members about it. There's lots of other ways to make your views known if it's so important to you.
As for the cases of a labor call to solidarity premised on racism, hetero/sexism, xenophobia, etc. Well, those are hardly calls for labor solidarity and I really _can't_ imagine anything like that happening today. In the past, it happened. Today? The example just doesn't make sense under current historical conditions.
kelley
"We live under the Confederacy. We're a podunk bunch of swaggering pious hicks."
--Bruce Sterling