Two questions:
1. Gotcha. But why is a contract with a "travelling clause" even legal? It evidently creates a union shop where none existed -- without benefit of a vote. Can an employer sign away the rights of his employees?
2. On whose behalf did Banta actually owe the $2.9 million in bennies? I can't imagine it's the contract labor from the nineties in Philly -- it has to be the company's regular staff. Doesn't it? Which brings us back to #1...
I think the "employees" were contractors hired to install Banta's tiles, and the contracts in question most likely covered the terms under which those guys were hired. If I read the article correctly, Banta later decided unilaterally to abrogate those terms, which led to the lawsuit.
And the $2.9 million would have been owed to the contractors ... and thereby also to the union.
I don't like the outcome here, but I think the judge probably ruled properly, based on contract law.