HRS §836-4
Witnesses are protected from arrest while traveling for court
If you come to Hawaii because a court ordered you to testify, you cannot be arrested or served with legal papers while you are here for that reason. This protection also applies if you are just passing through Hawaii on your way to testify in another state. It only covers matters that happened before you entered the state for the summons.
everyone
The statute, as written — Exemption from arrest and service of process
If a person comes into this State in obedience to a summons directing the person to attend and testify in this State the person shall not while in this State pursuant to such summons be subject to arrest or the service of process, civil or criminal, in connection with matters which arose before the person's entrance into this State under the summons. If a person passes through this State while going to another state in obedience to a summons to attend and testify in that state or while returning therefrom, the person shall not while so passing through this State be subject to arrest or the service of process, civil or criminal, in connection with matters which arose before the person's entrance into this State under the summons.
LawTrove is not legal advice. The summary above is a computer-generated restatement — the authoritative text is the official version linked above.