eavesdropping

[michaelpr]

I noticed at a game I had last night that the coaches always know what we (the officials) are saying in our huddles. In our association, we meet at the three yard line after a score before moving into position. Every once and while we have some infomation to pass to the other officials. As a wing official, I make a point to communicate with the other wing. Anyway, I have began to notice at this particual school they always seem to know what is said. Could they be using a device to eavesdrop on us? is this legal? ethical?