Suppose you are a law-abiding citizen, but a security guard wrongly thinks you stole something from a store. Without warning, the guard physically restrains you. Could you press charges for assault? (United States)
This will vary by state. In Wisconsin, according to state statute 943.50(3) the security guard could be immune from both criminal charges and civil liability for detaining you if they have "reasonable cause for believing" that you stole something, even if they later turn out to be wrong.
A... merchant's... security agent who has reasonable cause for believing that a person has violated this section in his or her presence may detain, within or at the merchant's... place of business where the suspected violation took place, the person in a reasonable manner for a reasonable length of time to deliver the person to a peace officer, or to his or her parent or guardian in the case of a minor. The detained person must be promptly informed of the purpose for the detention and be permitted to make phone calls, but he or she shall not be interrogated or searched against his or her will before the arrival of a peace officer who may conduct a lawful interrogation of the accused person. The... merchant's... security agent may release the detained person before the arrival of a peace officer or parent or guardian. Any... merchant's... security agent who acts in good faith in any act authorized under this section is immune from civil or criminal liability for those acts.
Most states have some form of a shopkeeper's privledge law. This affords a store the right to detain a person ONLY to determine if they are trying to steal property. The length of detention varies. Generally it is as long as necessary to determine if property is being stolen (e.g. check with a cashier, check surveillance videos, read the receipt, etc...) and should not extend beyond that but some states vary. New York for example allows detainment until the person can be questioned by a peace officer.
In summary anyone can sue or file a complaint for anything but under the law a lawful detention for purposes of investigating theft from a shop would not be impermissible.
An example of shopkeeper's privledge going awry is Macy's alledged racial profiling in 2015.
For more information a helpful law article.