I am a NJ not an AZ attorney, so this information is for general purposes. The law may be different in your state. In general, a process server is an officer of the court acting as the agent of a lawyer who is filing a proper law suit in a court of law. The law requires that the defendant (the person being sued) has the legal right to know what the case is, Being sued for causing an injury? Being divorced? Breach of contract? Who is suing you and why? All of this information is in the Summons and Complaint, which must be personally served on you. You have a right to privacy and not to have a trespass on your land. But every right is not absolute. You cannot claim that your right to privacy prevents a court of law from doing its job. You are much better off discussing with a defense lawyer how you can defend against the allegations in a lawsuit, than claiming your property rights have been interefered with.
A closed gate does not necessarily mean a person cannot come onto a person's property, especially if the property does not have a "No Trespassing" sign posted. This would probably be insufficient for a process server, as process servers are considered officers of the court and must be licensed by the court. If there is a problem using a private process server, a party can ask the Sheriff's Office to serve the papers. This means that a deputy would come out to the property.
Finally, even if a person avoids receiving the papers, a party can show the court that they have attempted to serve the person as Arizona law requires, but that the person is avoiding service. The court can then authorize alternative service. See Arizona Rules of Civil Procedure 4 and 4.1.
Finally, even if it could be charged as trespassing, it is highly unlikely that a county attorney's office would charge a process server with trespassing while attempting to serve papers.
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