[ChrisA]

They are perfectly fine as long as you stay away from the pit area with them.

For one thing they are very annoying, and for another they can really distract and hinder people working. If someone is trying to talk to someone about something that needs to be fixed before a robot goes out on the field and there is too much 'other' noise, then it can be very hard to communicate.

People trying to write programs usually like to have some peace and quiet so they can think through their code.

I can't really see any good reasons for them. I think though that when used properly, they can add a certain atmosphere at a robot competition, but not in the pits.