This answer indicates that it is always forbidden to count Jews directly.
However, can one count them if each person says his / her number? E.g. - when I was in camp, the counselor assigned us a number prior to boarding the bus when we went on a trip. Before we left, the counselor says, "Count off!". Each person shouts his / her number.
Is that method permissible, or is it the same as someone taking a direct count because he hears a specific number. In other words, to prevent counting does that mean that one can't use numbers at all regardless of whether he counts or the people say a number?