Every person subpoenaed as aforesaid, and neglecting to appear, shall also be liable to the party in whose behalf he or she may have been subpoenaed, for all damages which such party may have sustained by reason of his or her nonappearance: PROVIDED, That such witness had the fees allowed for mileage and one day's attendance paid, or tendered him or her, in advance, if demanded by him or her at the time of the service.
RCW 12.16.050
Result of failure to attend: RCW 5.56.060, 5.56.061.
When witness must attend: RCW 5.56.010.