California law requires that all labor must be hired through a union. Official Service Contractor management personnel are non-union. The local Teamsters Union has jurisdiction over all unloading and reloading of materials at all local convention facilities. My booth is too complicated to trust to union laborers. However, you can supervise and one of your employees can work with the union personnel.
Most workers are qualified skilled laborers.
I use an independent display house. Your display house must use union labor the same as the Official Contractor. Your display house or EAC will order labor from the same union as the Official Contractor. If you cannot comply with the above criteria, you may handle and set out the product you manufacture. However, all background materials - display boards, backdrops, stands or anything the product is displayed upon, attached to, or made a part of, must be installed by qualified union labor.