I once followed a course on safety in aviation, where the teacher suggested a technical measure to improve road safety: put a sharp rod on the steering wheel, pointing directly at the chest of the driver. Simple, cheap and depending on your exact goal, probably very efficient....

Now, I do not know about missiles, but wind turbines are a NATO concern: see for instance times online
Note that there are a number of mechanisms by which a wind turbine can interfere with primary radar. It is not only the fact that the energy reflected back on the wind turbine can trick the radar into thinking that he is seeing a genuine target. Wind turbines can by the way also impact secondary radar. See for instance Eurocontrol for more information.

It's rather that radars, ATC centers,... verify that information is not to old for display/use. As such, all equipment verifies different time sources (e.g.g internal clock, external GPS reference, DCF clock, etc)

With the addition of a leap second, you run the risk that some alarms will go off, indicating that there is a potential timing issue. This might cause the shutdown of certain systems.

Using NTP is not always an option: older systems cannot always connect to an NTP server (what with a 20 year old radar?), you need additional secured datalines, etc