My understanding is that in many countries this is the case, and judges are able to go below the mandatory minimum penalties when there's a good reason to do so. Of course you then get into the question of why then have the mandatory minimum, and that may be a way for Parliament or the legislatures in different countries to give an idea about the relative seriousness of offences.
I think what one has to look at is that sentences vary enormously, in large part because the behaviour that is being sentenced varies enormously and the role of the offender varies enormously. It is very easy to say that if this was a robbery with a firearm, we therefore cannot conceive of a situation in which somebody should get less than the minimum, except that as soon as one points out that the person being sentenced may have had a very minor role, may not have held a gun, may have been in the car waiting, and may have been an 18-year-old girl, the circumstances become quite different from one's image of an armed robber. In those circumstances, I think various countries say that the judge then has to justify it and go outside.
What we're really coming down to is the understanding that we have, or should have, some confidence in judges. I think one of the difficulties with the Criminal Code sentencing provisions at the moment is that even though we have a provision saying the sentence severity should be proportional to the harm done and the person's responsibility for that harm, what Parliament has done since the mid-1990s, when that was codified, is undermine that provision and make it more and more difficult to apply.
What I find interesting is that in many instances we're not really addressing the very difficult issue of deciding what we mean by proportionality and at what level we should be doing it. We're saying that we don't really care about those nice details, that we want to simply sentence.