Currently we have the parameter $smwgAdminRefreshStore which prevents to start a data refresh via Special:SMWAdmin if set to false. However it is still possible to set up the store as such via Special:SMWAdmin. I think it would be very useful to be able to disable this functionality on selected wikis, too. Still I can think of circumstances there on might want to disable setup, but not data refreshs. Thus merging both in one parameter would not be preferable.