IOS – Does Find My iPhone upload its location when connected to iTunes via USB

I'm afraid you're completely right. Apple does even make a statement on its website about it:

However, there are some alternatives.
But since there is no way to come up with a work around on this problem, 3rd party software, like Undercover allows you to store the latest locations of an iDevice. Where Find my iPod touch will only show you the current location (it doesn't show a history of locations I think), Undercover will save its latest location, as they say on their FAQ page:

What happens if Undercover is launched when a phone is not connected to the net? Will it still transmit its location?

If Undercover is launched on an offline device (no 3G or Wi-Fi), its location is saved. As soon as the device goes online and Undercover is launched again, saved locations will be transmitted.

Here's what Apple says:

Because of how Find My Mac works, you must deselect the box next to Find My Mac in the OS X System Preferences > iCloud pane to remove your device from your iCloud Find My iPhone, iPad, iPod Touch, or Mac device list.

One of the ways this persistence is implemented is by writing a Find My Mac token to NVRAM, the persistent memory in Intel Macs. You can see this token by running the following command in a terminal:

nvram -p | grep fmm

On my Mac, the result includes my name, Apple ID, and the name I gave the computer, along with some encoded information that probably includes a key of some sort.