Summons and subpoena are not the same. One site says subpoenas are for criminal cases and summons for civil cases. I stated in another article that there are three kinds of subpoenas and have been asked about that. There are two kinds of subpoenas but they can be three different uses for them depending on what I was told. You need to know the difference unfortunately even in the photography business. It is a business so be prepared for the darker side of it.
First the idea that they are civil and criminal is just plain wrong. If you read these articles you will find that I have tried to keep things simple and I will continue that here. I recommend that you get a Black’s Law Dictionary or use their online version.
Simply put a summons is a document that is issued by the court or a person associated with the court that notifies a person that there has been a case filed against them and they are required to respond usually a personal appearance. If they do not appear there will usually be a default judgment issued against them. A summons is a notice with a court date assigned for the hearing.
Order of a court naming a party that a case involving it is filed and an appearance must be made.
Law Dictionary: What is SUMMONS? definition of SUMMONS (Black's Law Dictionary)
A subpoena is different. It is for a person to supply information, to appear and testify or to do both. That is the reason for the 3 I mentioned before.
Subpoena: It is a writ or order directed to a person, and requiring his attendance at a particular time and place to testify as a witness. It may also require him to bring with him any books, documents, or other items under his control.
With that being said I suggest you spend more time worrying about service. Getting a summons or subpoena issued via the court or attorney is not very hard. The process of service has many meanings and can be handled in different manners in different jurisdictions. I strongly suggest reading Personal Service, Service by Publication, Service of heirs, Service of Process, Substituted Service and Service of Practice. If that is not enough, do not forget that some courts are now allowing service by social media. I think you can see that you have options but if someone wants to ignore it so be it.
Here is a comment by an attorney concerning this type of situation. http://forum.freeadvice.com/other-crimes-federal-state-4/subpoena-civil-suit-9723.html . Read # 2 and it should give you an idea of how things work in the real world.
I am not an attorney. These are my personal opinions and general information only. These are not legal advice and should not be used as such.