Do you want to put your parents who live on the other side of the country or your brother who lives nearby? If your wife is likely to panic and freak out, perhaps a close friend could be the contact and they could break the news. Hospitals need a next of kin there in case of severe injuries to give permission to treat. The sooner they can reach you at the hospital, the more help they can be. Most phones these days have a lock on them, so without knowing your passcode contact information cannot be accessed. The waiver is often the only thing the dropzone has to contact anyone.
And don't forget to keep it updated. If phone numbers change or they move, make sure the waiver is kept up to date.
