That difference is exactly what Anne and others at the table have mentioned. When the ion scanner rings, it is supposed to be followed with a threat risk assessment. It is usually followed by some kind of interview, but there is no follow-up search. My understanding from talking to people is that the follow-up search is not conducted. Often they'll ask why it's ringing positive, but people have no idea. They have no good answer. The lack of a good answer is taken as evidence that they must be doing something wrong, and then visits are denied. There is a lack of follow-through, of coming up with what I think is an effective assessment of visitors.
The other problem is the disjunct between what the policy says in terms of how the machine should be operated and the fact that they found themselves, which is that they are not always operating the machines according to the manufacturer's specifications and they are not always following the protocols in terms of cleaning.