Consider the following situation:
A businessman B
is negotiating with a group of foreigners C
who are widely (and with a reason) suspected of having an "alternative" view on business ethics. B
thinks that the crooks might betray themselves by talking to each other in their language which B
does not understand, so he asks his friend F
(who is a native speaker of the foreign language) to listen in on the negotiations (from the next room when negotiating in person or on a second phone line when negotiating over the phone). So, C
do not know that there is a third party F
listening to the negotiations.
Alternatively, B
records the conversation (without C
's knowledge) and lets F
listen to it off-line.
If this behavior unethical?
Obviously, the answer may depend on the country in question (I have the story from F
who was quite proud of his role), so let us limit ourselves to USA (and the West in general).