[sudonem]

And it’s easily altered.

[ranger_danger]

It can still be correlated with past IDs by countless other methods in order to keep tracking you further.

[kvuj]

But then you're using other methods, you're not using the ID as tracker. In fact if you just remove it, it eliminates this entire discussion.

[ranger_danger]

The trick is to combine it all, which is what MS is doing. For example your MS account stores any GDIDs that you've logged in with.

If you use a different identifier to track changes in a GDID/machine-id/etc., that means you can continue tracking using mainly just the new machine-id, but you should always keep trying to correlate it with other things in case it changes.