When I deploy a map service on ArcGIS.com and edit it to configure pop-ups, I'm faced with a dilemma. Say I have a map with the same data shown in different groups visible at different scales using different symbology. If I enable pop-ups on all scales, when the user queries the map, pop-ups are shown for the data at all scales, producing duplicate pop-ups. If I enable pop-ups at only the largest scale and the user happens to turn off that scale, when they query the map, no pop-ups are visible. The ideal scenario would be to enable pop-ups at all scales and when a user queries the map, only the visible data is queried, thus returning a single pop-up. It then doesn’t matter which layer(s) the user has turned off. As long as they see data and query it, a pop-up will be returned.