Can an employee of some store detain you if you don't show your receipt on your way out? Or if you don't let them search your bag? In Utah, yes, they can!
Can a police officer arrest you for not showing a store employee your receipt or allowing a store employee to search your bag? In Utah, yes, they can!
If they do, can you bring civil or criminal charges against them (the peace officer or the store employee, or both) for unlawful detention? Slander? Defamation of Character? In Utah, no, you can't!
For Example
If you're at BestBuy, CostCo, Sam's Club, or any other store and you refuse (for whatever reason, including if you're just in a hurry), they have the right under Utah Law to detain you for a "reasonable amount of time" and in a "reasonable manner" (though those aren't defined in the Law).
They can detain you for a "reasonable amount of time," which most judges will agree is "until the police arrive." But then the peach officer will no doubt let you go, right? Well, not without checking your receipt, your bag, and frisking you (all of which the peace officer has the right to do, as codified in Law).
But what about arresting you? Can the peace officer arrest you just because you didn't show your receipt or open your bag?
Yes, "any person the officer has reasonable ground to believe has committed a theft" can be arrested without a warrant.
But what is that "reasonable ground to believe [you have] committed a theft", what constitutes that? "A charge of theft made to a peace officer ... by an employee of a library, or by a merchant, merchant's employee, servant, or agent constitutes a reasonable ground for arrest ... "
But wait, it gets worse!
Furthermore, "the peace officer is relieved from any civil or criminal liability" resulting from the arrest. And, if you keep reading in sub-section 14, the " ... merchant, or merchant's employee, servant, or agent who causes the detention of a person ... , or who causes the arrest of a person ... , is not criminally or civilly liable where he has reasonable and probable cause to believe" that you store something (in other words, if you didn't show them your receipt or let them inspect your bag).
In Summary
If you refuse to show your receipt or allow your bag to be searched by a store employee, they have the right to detain you until the police arrive (hours?) by any reasonable means (blocking your way out? handcuffing you? physically restraining you? assaulting you? battering you?), when the police officer arrives all they need is the charge of theft be made by the employee to arrest you... AND YOU CAN'T BRING CRIMINAL OR CIVIL CHARGES AGAINST THEM!
Don't take my word for it, read it for yourself
77-7-12. Detaining persons suspected of shoplifting or library theft -- Persons authorized.
(1) A peace officer, merchant, or merchant's employee, servant, or agent who has reasonable grounds to believe that goods held or displayed for sale by the merchant have been taken by a person with intent to steal may, for the purpose of investigating the unlawful act and attempting to effect a recovery of the goods, detain the person in a reasonable manner for a reasonable length of time.
(2) A peace officer or employee of a library may detain a person for the purposes and under the limits of Subsection (1) if there are reasonable grounds to believe the person violated Title 76, Chapter 6, Part 8, Library Theft.
77-7-13. Arrest without warrant by peace officer -- Reasonable grounds, what constitutes -- Exemption from civil or criminal liability.
(1) A peace officer may arrest, without warrant, any person the officer has reasonable ground to believe has committed a theft under Title 76, Chapter 6, Part 8, Library Theft, or of goods held or displayed for sale.
(2) A charge of theft made to a peace officer under Part 8, Library Theft, by an employee of a library, or by a merchant, merchant's employee, servant, or agent constitutes a reasonable ground for arrest, and the peace officer is relieved from any civil or criminal liability.
77-7-14. Person causing detention or arrest of person suspected of shoplifting or library theft -- Civil and criminal immunity.
(1) A peace officer, merchant, or merchant's employee, servant, or agent who causes the detention of a person as provided in Section 77-7-12, or who causes the arrest of a person for theft of goods held or displayed for sale, is not criminally or civilly liable where he has reasonable and probable cause to believe the person detained or arrested committed a theft of goods held or displayed for sale.
(2) A peace officer or employee of a library who causes a detention or arrest of a person under Title 76, Chapter 6, Part 8, Library Theft, is not criminally or civilly liable where he has reasonable and probable cause to believe that the person committed a theft of library materials.