I used the explorer at my first competition hunt earlier this year. It was crowded but I experienced very little interference. My only problem was a blister at the base of my index finger from swinging so long. Based on the number of coins planted and the number or people hunting, I got twice the average per hunter, so I think I did OK.
Just open up a box in the upper right corner that accepts everything, but don't get too fancy. I made mine just reject zinc pennies but later found out to my horror I rejected tokens as well (I thought the tokens were colored copper pennies and they were acually bronze tokens - I'll listen better next time!). But I sure found lots of tokens from previous years hunts.