In WA, a store has a civil cause of action against alleged shoplifters even if the merchandize is recovered. See RCW 4.24.230 (Liability for conversion of goods or merchandise from store or mercantile establishment, leaving restaurant or hotel or motel without paying – Adults, minors – Parents, guardians – Notice). The statutes are at http://apps.leg.wa.gov/rcw/ .
If the alleged shoplifter is a minor, the store has the right to sue the minor's parents.
Legally, the civil cause of action is separate from any criminal charges that the prosecutor may pursue. That is, paying the civil demand does not stop criminal prosecution. On another hand, the store may cooperate with the defendant in presenting a compromise of misdemeanor to the court asking the court to dismiss the case against the defendant.
Some stores will sue persons who do not agree to the settlement offers. Some stores will not sue.
The suing stores likely reason that it is an easy win as the stores likely have videotapes of the alleged shoplifting as well as signed statements from the alleged shoplifters.
The nonsuing stores likely reason that actually going to court may not be cost effective since some persons have no money to pay any judgment.
No one can or should tell you whether to pay. That is a decision for you to make.