Make `--tracking` off by default

[jfinken]

Given CPU performance implications, turn event tracking off by default.

• I believe that would simply be setting this to false but correct me if I'm wrong
• If correct, I'd be happy to submit a quick PR. Please let me know the correct destination branch.

[alsora]

Yes, that's the line to change.
I would say to target master for now. We can figure out what to do with the branches as a separate effort and, if needed, cherry-pick the PR.