So, what is the correct info?
I can and have been in the Smokey mountains, 20 miles from any data connection like WiFi and cell towers, and the GPS locks quickly.
The GPS will work 100% stand alone with no data. (you will need maps in memory for it to be useful of course)
But, if the GPS has been unused for a LONG time, it may take a long time to find the satellites and catalog them. If you have a data connection, it can download info on satellites online to help find them quicker. Once they are found, the data connection is not needed for days. And not really needed at all, it just make it quick if your satellite data is stale.
Then of course there is the location services that use WiFi or cell towers to help locate you. These are not GPS and have nothing to do with GPS and are not very accurate. But they are good enough for looking up your location for the weather or such, and use low power.