California Code, Civil Code - CIV § 846.2

No cause of action shall arise against the owner, tenant, or lessee of land or premises for injuries to any person who has been expressly invited on that land or premises to glean agricultural or farm products for charitable purposes, unless that person's injuries were caused by the gross negligence or willful and wanton misconduct of the owner, tenant, or lessee.  The immunity provided by this section does not apply if the owner, tenant, or lessee received any consideration for permitting the gleaning activity.