Currently, (as per TestComplete help) TestComplete only checks for unexpected windows when the script performs an action (Click, DblClick, Activate, etc.). The check does not happen when the scri...
What I mean is that other tools offer things like Recovery Scenario Manager etc. where you can define such scenarios separately (without including all such external situations into your code in each case) and attach it to the scripts when needed. If such a popup is displayed, the recovery scenarios defined will kick in and close the popup. The actual script need not handle it.
This approach can help in defining all the unexpected scenarios separately without making your script code more and more complex. If there are 10 such scenarios that can happen over the duration of a script, then you don't have to repeat this in each script or in each function.
TestCompelte does not have a Recovery scenario handler separately as far as I know. When I say 'Unexpected', it means that the popup does not occur in a 'normal' case but there is a possibility that it will be shown and we can define the recovery to push the 'Close' button etc.