We could create a visualization that adds an icon to the widget footer listen all related alerts for the current report and selected date period.
Eg if someone creates a PageURL alert we could show all alerts related to this in the "Actions => Pages" report. If there are multiple alerts available for the selected report we could also display the number of alerts "in the alerts icon" or on top of the icon.
Alternatively we could maybe sometimes show alerts even inline. Eg if there's an alert checking for pages starting with /index, we could give all those pages a different color / background color / icon / ... but this is probably not easily doable.