Just some info for people outside the US:
In many regions, TOS clauses forcing arbitration are illegal, and resultantly there is nothing to which you need opt out.
This includes the entirety of the European Union, under the GDPR legislation.
This also includes most of Canada, including Ontario, Quebec, and barring a few exceptions which do not apply here, British Columbia.
https://gist.github.com/Rapptz/c93697c9d59ec2f0d8071b7d0e907632#gistcomment-2735825