[mindslight]

The message itself ("this call may be recorded") has given you consent the record the call, without needing to play your own version. The point was that this doesn't mean the employee themselves has consented.

Then again, the caller could use similar reasoning of saying their assistant placed the call and waited on hold, and only then did they get on the line. Or really any phone conversation where a new party comes on the line after the recording has started.

I think the call center employee would have a pretty hard time arguing some expectation of privacy regarding your recording, when their employer has made it clear that the call can be recorded. I'd be interested in any precedents to the contrary though.

However, talking in terms of "consent" might just be a red herring. A company hasn't actually obtained your consent by playing a notice that they are recording the call. What they have done is destroy your expectation of privacy.