I'm not sure why this sounds like an exercise in "Blame The Lawyer."  It's not the lawyer who is preparing the tax returns, right?  So your client / friend / kindergarten playmate should have asked you if there is anything you would need to prepare the tax returns.  And you would have pointed out the part in the 1065 instructions that says, "Foreign partners without a U.S. identifying number should be notified by the partnership of the necessity of obtaining a U.S. identifying number."

Then someone has to deal with the FinCEN reporting requirements.   Maybe you can blame the lawyer for not telling him about that one.  I think the rule for foreign partners on that one, though, is that a scan of the passport is acceptable.