On Friday, October 7, 2016 at 10:29:40 AM UTC+2, krasw wrote:
Our national competition rules are translation of Sporting Code 3 Annex A, and I've done the translation myself. Some paragraphs were omitted because they were needed in international events only, and some were slightly modified. Since we do not have IGC class structure, that paragraph was rewritten completely. The job took few evenings and 99% of the effort was translation. We update rules every year after Annex A update (usually a line or two). Contest organisers provide local prodecures suited to their needs. This has been going on for at least a decade without any problems.

Same goes for Sweden.
We have out national rules, which are based on the IGC SC3. There are a few national adjustments, but not more than that I can more or less participate in a IGC completions without spending hours in reading and understanding SC 3.
When we arrange Open “international” competitions in Sweden do we usually use SC3 to avoid the issues that our guests does not understand Swedish and therefore cant not read our national rules.