In Tony Ortega's log of the testimony of Jane Doe 1 in the Danny Masterson rape trial, Jane Doe 1 testifies that she didn't report Masterson earlier because of Scientology's high crime policies:
Q. Was there a reason you didn't go sooner?
A. Yes. Because I was a Scientologist and Mr. Masterson is a Scientologist and you cannot report another Scientologist in good standing to the authorities.
Q. What was your understanding if you did?
A. It was a high crime, and it would come with expulsion, and my understanding is you can't talk with at all someone who has been expelled. Declared a suppressive person was what it was called and it would have major ramifications. My life would be over. I wouldn't see my parents, or my family. I wouldn't have a place to live or work. I wouldn't have a place to go. (Emotional.)
The Dianetics and Scientology Technical Dictionary defines high crimes as simply "suppressive acts":
HIGH CRIMES, suppressive acts. (ISE, p. 48)
while the glossary for the Introduction to Scientology Ethics Hatting Course has this entry:
high crimes: actions or omissions undertaken knowingly to suppress, reduce or impede Scientology or Scientologists.
One of Scientology's most important books, Introduction to Scientology Ethics, lists 3 pages of High Crimes, also known as Suppressive Acts, including:
3. Public statements against Scientology or Scientologists but not to Committees of Evidence duly convened.
4. Reporting or threatening to report Scientology or Scientologists to civil authorities in an effort to suppress Scientology or Scientologists from practicing or receiving stan- dard Scientology.
5. Bringing civil suit against any Scientology Organization or Scientologist including the non-payment of bills or failure to refund without first calling the matter to the attention of the Chairman at World Wide and receiving a reply.
6. Writing anti-Scientology letters to the press or giving anti-Scientology or anti-Scientologist evidence to the press.
7. Testifying as a hostile witness against Scientology in public.
16. Delivering up the person of a Scientologist without defense or protest to the demands of civil or criminal law.
Further, leaving Scientology is itself a Suppressive Act (as is requesting a refund of Scientology fees, even if you're not wishing to leave the organization):
B. DISAVOWAL, SPLINTERING, DIVERGENCE
1. Public disavowal of Scientology or Scientologists in good standing with Scientology Organizations.
2. Announcing departure from Scientology (but not by reason of leaving an organization, a location or situation or death).
3. Seeking to resign or leave courses or sessions and refusing to return despite normal efforts.
4. Resignation of all certificates, classifications and awards (but not posts or positions or locations).
5. Demanding the return of any or all fees paid for standard training or processing actually received or received in part and still available but undelivered only because of departure of the person demanding (the fees must be refunded but this high crime applies).
It defines Suppressive Acts:
Suppressive Acts are defined as actions or omissions undertaken to knowingly suppress, reduce or impede Scientology or Scientologists.
Based on these writings, many Scientologists come to understand that speaking out against another Scientologist, especially to legal authorities, will be considered a Suppressive Act - a High Crime - and will lead to their expulsion from Scientology and subsequent shunning by other Scientologists, frequently including their family, friends, employers, and business contacts.