In Illinois, your spouse, ex-spouse, live-in, "significant other", relative, or any person with whom the accused has or had a family or romantic relationship may apply to a judge for an emergency order of protection. This is done without any notice to the person who is supposedly a danger until AFTER the order is issued. It is then valid for 10 days, when a hearing is to be held. Your firearms MAY be ordered to be held by the local police until after the scheduled hearing, and longer if a "permanent" order of protection is signed. A friend of mine, and a city police officer, was on the wrong end of such an order due to a vicious, manipulating ex-wife who thought she could gain more child visitation time this way. Unfortunately, she had to allege facts, and the day after the order was served I showed the judge that her alleged "facts" were, in fact, lies. He suspended the order. She failed to show up on the hearing date. We went to family court and got her visitation time reduced, based only partly on her lies to the court.
The important thing to note is that a protection order was issued without the person whom the order was against being given any notice or opportunity to appear until AFTER the order was issued! His due process was to come 10 days later! In most areas of the state, his guns would be gone and he would be out of work for 10 days. THIS is "due process" in Illinois. I can't believe California will be inclined to interpret due process in a stricter manner than has been done in Illinois (and other states) for years.