Washington State law [RCW 42.56.070(8)] prohibits the disclosure and use of lists of individuals for commercial purposes. Signing on the next card certifies that if you use, or allow others to use, such records for commercial purposes, you may violate the rights of the individuals listed and may be liable for damages.
"Commercial purposes" means that the person requesting the record(s) intends that the list will be used to communicate with the individuals named in the record(s) for the purpose of facilitating profit-expecting activity.