AFAICS, what is proposed are areas without magic, which may be created by any of the means mentioned.
This has been proposed before, and the reasoning was that the crystal, which is the source of magic in Yliakum, might be shaped uneven and thus send more or less (or none at all) \"magic radiation\" to the places. I, however, don\'t like this idea. To artificially create such an area would require quite a lot of magic, but that might be feasible. However, the sources of the field need to be located outside the field to not get affected by it, so they would be prone to magical attacks. This, however, might be feasible, as long as the areas are reasonably small.