I imagine that the aim of prohibiting links to "commercial sites" is (or should only be) to keep GS away from becoming a tool of sales promotion.
If partial portions of a "commercial site" have no effect in promoting profit, especially if the information contained in such portions are useful and interesting to the fans of figure skating, the brousing of such portions do not mean any profit to the "commercial site", hence the links to such portions should be exempt from the prohibiting, IMO.
"Announcement" thread says "Links to commercial sites such as Champions on Ice, Stars on Ice and other touring/production companies are prohibited."
But such links are done in GS forums and are welcomed by moderators.
Indeed it should be welcomed since it's at each one's discretion whether to go and see or not. Introducing the official sites of skating shows are nothing to be prohibited unless it is posted by the organizer/insider for promotion purpose.
The more so on other useful information on "commercial sites", IMHO.
But I might be blind in some ways, so please share me your insights.