What circumstance does a registar reveal private whois information?

[hxQ&S8ZaVn9e]

If you have privacy protection enabled on a domain name under what circumstances would the domain registar reveal the registrant information to a 3rd party or authorities?

 

[DomainBop]

Law enforcement subpoenas, court orders and other legal processes received, violation of the domain registrar's TOS, compliance  with ICANN rules and UDRP/trademark disputes, registrar believes you are violating the law or engaged in spamming, non-payment/cancellation of the privacy service are the most common reasons .

Here is Tucows:

• Right to Suspend and Disable. We shall have the right, at our sole discretion and without liability to you or any of your Contacts, suspend or cancel your domain name and to reveal Registrant and Contact Whois Information in certain circumstances, including but not limited to the following: (i) when required by law; (ii) in the good faith belief that disclosure is necessary to further determination of an alleged breach of a law; (iii) to comply with a legal process served upon Tucows; (iv) to resolve any and all third party claims including but not limited to ICANN's or a Registry's dispute resolution policy; (v) to avoid financial loss or legal liability (v) to avoid financial loss or legal liability; (vi) if we believe that you or one of your Contacts is using the Whois Privacy Service to conceal involvement with illegal, illicit, objectionable or harmful activities; or (vii) to transmit SPAM, viruses, worms or other harmful computer programs.
• You understand and agree that, in the event that we receive a formal complaint, notice of claim or UDRP, that we will have the right to disable the Whois Privacy Service pending final disposition of the matter.

GoDaddy's Domains by Proxy has a similar (but longer) list of things that will cause them to reveal your identity: (see #4 https://www.godaddy.com/agreements/showdoc.aspx?pageid=DOMAIN_NAMEPROXY )

 

[Nyr]

Ask your registar / read their ToS.

 

[BlaZe]

If you do anything against their ToS.

If you host a website defaming the country, hatred websites, etc. the countrymen might come to get you and they need information from the registrar >.<