How to handle leap seconds
http://www.theregister.co.uk/2011/09/19/google_has_to_lie_to_computers_about_time/
Windows does essentially the same thing: Ignores the leap second an treats the updated time after the event as clock skew, adjusting over an hour or so.
Your junior devs will never be good enough to handle leap seconds correctly.
Your server clock is not that accurate anyway.
It doesn't matter for most applications.
If you are not sure whether it matters for your application, it doesn't. If it did you would know because you would have an atomic time source in your lab.