You hear this at conferences all the time; I did on Friday.
You're in an assembly hall. The speaker or panel wants to field questions; the moderator then recognizes an interested party. The mic jockey is coming to the speaker who brushes off the him or her saying "I don't need the microphone."
Yes, you do:
- If the event is being recorded, you need a mic to be heard.
- If the event is being projected on to a large screen or remote monitor, then there are people too far to hear you.
- Most assembly halls are noisy: some people with typical hearing will need the amplification.
- Even in quiet spaces, people with impaired hearing will need the amplification.
Please wait for the microphone. Oh, and keep it short.