Speak with your own copyright attorney if this question was motivated by an actual dispute you're having with someone. I'd be happy to be proved wrong with a citation to any case law holding otherwise. I've never heard of someone being sued for copyright infringement for simply watching an unlicensed streamed event - likely because it's not a violation of any of the exclusive rights granted to a copyright owner. That RIDICULOUS claim, however, can no longer be brought because it's now been held that viewing an internet stream is NOT a violation of Section 553. The viewer did not defend himself and so judgment was entered against him. The claim, however, was NOT copyright infringement but rather the unlawful interception of a 'radio communication' in violation of the Communications Act.
The answer is, yes, at least one copyright owner has filed suit against an internet user for simply watching an unlicensed, streamed program.
