There is a trade off on the "T" recommendation of the "UPDATE" acronym protocol.
If you Turn off your wifi or computer you could miss the Apple security updates that are (under some circumstances) automatically pushed to your computer. ...
True. But then there are many of us who don't permit "automatic" updating of anything as a matter of course, in addition to which some of us log in and off the Internet given our "archaic" access.
I don't think you can opt out of the automatic updates Ira is talking about, but the question remains how long after you start up it takes Apple to recognize that you're "on the air" and push the update through if you were shut down when they first tried.
If it's "immediately", you lose virtually nothing by shutting down.
