I think its a good idea.
I also think that, as well as reffing the racing, the marshalls should be kept in touch too. twice on sunday I lost whole laps due to the marshalls watching the racing and not the track in front of them

, and when I was marshalling, me and the guy next to me ended up running across the track to marshal cars over the other side of the track, because of the same reason.
Yes I had to shout the marshal, but I didn't use an fruity language. I stopped doing that years ago, its not fair. if its my own fault I will stay silent for a short time until i can see that marshalls aren't looking then I will shout them. but i don't agree with swearing on the rostrum.
I think when I heard some swearing on sunday there was a 'younger' racer on the rostrum too, and it's not the sort of lanuage they should be hearing.