Warned
A character who is Warned has had a Come To Jesus and, if they do it again, stand to be severely punished.
Those who are Warned may not speak to any officer of your sect in public without first being spoken to and they may not contradict any sect official. If a character breaks this censure, they can either take the consequence of further negative status (Disgraced specifically) OR apologize through offering a minor boon (Camarilla), a favor (Anarchs), or a Sworn Debt (Sabbat). Alternative restrictions may be placed by the person who is issuing the Warning (for example, the Keeper of Elysium kicks you out of Elysium for a few weeks unless Court is being held there). If a staffer believes the alternative restriction is inappropriate, they may overrule it and impose the default censure.
Before ever issuing Warned to a character, check in with their player before you do it ("Hey, your character did X, my character believes that she should be Warned due to Y, but it's all IC, let me know if you have an OOC issue with it"). Keeping up with each other OOCly is important to create healthy, enjoyable IC conflict and checking in OOCly before you do something antagonistic ICly goes a long, positive way toward creating a comfortable environment.
Why Would I Get Warned?
Camarilla
The Keeper Of Elysium may warn someone who either insults other characters of station/status within Elysium (e.g. a Neonate insulting an Elder or Ancilla or Sect official). The Keeper may also issue a Warning to someone who causes some minor physical injury to someone of low station in Elysium (such as a Ghoul), although in many cases Disgraced may be issued instead.
The Harpy may warn someone who is breaking a minor boon.
The Sheriff may warn someone who is disrespecting an established law of someone's Domain.