Bugs in the boardroom are not common but the potential loss is so great that they can't be ignored. To decide if a sweep should be done evaluate the following:
1) Threat sophistication, how capable are the most likely eavesdroppers?
2) Vulnerability, would it be easy to get a hidden transmitter under the table?
3) Risk, what is at stake, how much damage would the organization suffer if the strategic discussion gets to competitors?
In some cases the threat sophistication (a rival company) is high but the vulnerability (them getting past security) is low. Other situations have a low threat sophistication (an unhappy employee) but high vulnerability (someone who is already inside).
Often the information to be discussed is just so critical that it is necessary to perform a sweep for listening devices even before the threats are known.
This is like buying fire insurance but better. Fire insurance can't prevent the fire.
If you suspect eavesdropping call for a Bug Killer® from Future Focus.
Before the big meeting we discovered a wireless microphone.
It was removed immediately.
Wireless microphones should never be in the room when important discussions are being held. They broadcast voices over a wide area - often they are easily intercepted in the parking lot outside.
Of course, wireless microphones offer convenience and may be returned to the meeting (by an eavesdropper or a well-meaning employee).