These rules can also be found in the pinned post on the FB group https://www.facebook.com/groups/FixTheTaxTreaty/
Clarification on how tax professionals can participate in the Facebook group:
Participation in the group by tax professionals can help provide valuable insight into the current state of US tax law, and should be encouraged within certain boundaries. The best way to identify yourself as a tax professional is to put your qualifications and contact details on your public Facebook profile.
The group has a strict “no advertising” policy. This means that tax professionals should not offer their services in posts or comments. Furthermore, tax professionals should not initiate contact with group members via Messenger. Group members will see on your profile that you are a tax professional, and if they are looking for help and are impressed with what they see in your comments or posts, they will contact you. Any breach of this policy will result in immediate removal from the group.
Fearmongering of any sort will not be tolerated. This includes telling people that they must file. The IRS has limited ability to enforce US tax law on those with no US ties or assets. Failure to file a tax return will not result in extradition, and there have been no reports of noncompliant expats receiving any notices from the IRS without a previous paper trail in the form of 1099s or recently filed returns. There are many reasons an expat may wish to file US tax returns, but this is a personal decision based on one’s personal circumstances and tolerance for risk.