But if you really want to give these objects nowhere to hide, use a preflight profile to reveal them.
From the Preflight Panel menu, choose Define Profiles. Click the + (plus) button to create a new preflight profile. Give your new profile a name, and in the IMAGES and OBJECTS options, select Hidden Page Items (plus whatever other conditions you want InDesign to check for).
Click OK, and then select your new profile from the panel menu. If there are any hidden objects, they will be listed as errors and you can double-click them in the panel to jump to their location in the document.
But you still won't see them until you show them (by pressing Command+Option+3/Ctrl+Alt+3, or choosing Object > Show All on Spread, or clicking the object’s Show/Hide button in the Layers panel).
With tools like these you can be the World Champion of Hide and Seek
(at least inside InDesign).