They could have overlooked this, but it would not seem odd to say it's being recorded, for whatever reason. Or even having a sign that says "audio and video recording in use" would probably suffice.
Yes, it's one party consent, two party notification. There was clear expectation of privacy (it wasn't a public meeting in a cafe, or a press conference). Hiding the identity of the outsourcing guy might legally change things -- I actually have no idea. The firm is trivially identifiable, but it might be enough. Regardless, it's irresponsible.
More ice blocks and real guerilla marketing, less bragging about violating employment laws or wiretapping vendors, please.
