Of course they say free advice is usually worth what you paid for it... nevertheless, here is some.

While technology becomes obsolete more and more rapidly, one thing that stays constant is the computer-chair interface -- in other words the user. Sometimes it's just as important to understand the user as it is to understand the equipment and software. One thing that I have learned about users is not to ask them who messed the darn thing up. It may not be incredibly profound but I do think it's a useful bit of information to know. To some it might seem obvious but a surprising number of people in internal tech support seem to think that it's a good idea to ask the user this question. Experience has taught me that it's a terrible idea. The following piece from my training materials explains why.

There is little point in asking the user the question "Who is responsible for this?" when the user has not told you already. This is not only counterproductive from a morale standpoint, but from a statistical one as well. For example, when you find that a cable has been disconnected, in general the user will not be the one who disconnected it. This is so because, if he had been, he would have known what the problem was. Furthermore, if the user knew that someone else had been handling his terminal, he would have asked that person what they had done, and again he would have known what the problem was. So you can see that when you discover that a cable has been disconnected, and you ask the user who disconnected it, the answer will most likely be "I don't know." On those rare occasions when he does know, it will be either a co-worker, the user himself, or a stranger. If a co-worker with whom he works closely is responsible, the user will most likely say that he doesn't know, because he does not want to cause trouble for his co-worker, who he has to work with every day. If the user himself is responsible, he most likely feels either guilty or foolish for having caused the problem. In only two percent of cases will he admit to having caused the problem. So you stand a 98% chance of hearing "I don't know" even when the user himself is responsible, and knows it.

If a total stranger disconnected the cable, for instance a cleaning person or a service technician, there is a strong likelihood that the user did not see this, and so again his answer is "I don't know." Only in the rare instance where the user saw a person unplug the cable, and does not have to regularly work with that person, is he likely to tell you or be able to tell you who unplugged the cable. But if this happens, since the user saw the incident, he will, in a majority of cases, either plug the cable back in, or ask the person who unplugged it to plug it back in. So you can see that when the user does know who unplugged the cable, he is very unlikely to need to call you at all, and if he needs to call you, he is unlikely to be either willing or even able to answer the question for you. Therefore it is generally pointless to ask. If you do not ask, you stand a better chance of being called the next time there is a problem, because you have not caused the user to feel foolish for not knowing or guilty for not telling. If you can avoid associating a call to you with bad feelings on the part of the user, you are more likely to be called the next time. If the user comes to associate calling you with feeling bad, they will try to find ways to avoid calling you, even when the call could solve the problem more quickly and easily. This same argument applies to most problems. In general, if the user did not call and tell you "so and so did this to my device" then there is little point in asking about it.