GOAL: We want to remove default themes in classic sites (STS#0)
Obstacle: There is no OOTB way (as far as I know)
The themes are located in every site collection in Theme Gallery. I remove the '15' folder from Theme Gallery. When my users go to 'Change the Look', they get a blank screen. That seems to be a very un-perfect solution for us.
Question: Has anyone tried that? Implemented it? Did you get any side-effects?