At this year’s American Bar Association Conference in San Francisco, for example, LinkedIn general counsel Erika Rottenberg told a roomful of people that her company asks firms about their work for non-practicing entities — and that dissembling could be a deal-breaker.

“While only a few [companies] have laid down a blanket ‘no one who represents trolls will represent us’ rule, I think the general sense in most Valley firms today is that as a practical matter you have to pick a side,” Mark Lemley, director of the Stanford Program in Law, Science, and Technology, wrote in an e-mail.