I spent many years working in retail Loss Prevention, and as part of my duties spent countless hours in court dealing with numerous cases related to both customer theft and staff theft, and some cases related to customers v staff. Retail theft by customers is a serious issue for some stores, but nowhere near what it is made out to be across the retail spectrum. The retail industry likes to put large numbers out there because it allows the industry to factor in the costs of loss due to “customer theft” in its pricing models, and can point to theft as a reason when complaints get raised about the cost of goods. The majority of losses suffered by the retail industry involve staff stealing and goods damaged by staff due to mishandling - that’s where the big loss dollars reside.
Consumers need to remember though that checkout staff are only doing their job when requesting to see your bag, so don’t shoot the messenger - if you want to complain/get upset about having your bag checked ask to see the store manager and take it up with them. They can request to check your bag and you can refuse, that is your right. If you choose to do so though please remember the following, do so politely but firmly and please don’t be aggressive or abusive. The staff member is not personally calling you a potential thief, it is the business owner making that call. Also remember that you are on someone else’s property and the business owner or their representative can revoke their permission for you to enter their premises freely for not complying with their requested conditions. That is the only legal standing that the sign at the front of the store has (yet to see/hear of a business owner throwing away customer dollars like that though lol).
Whether you choose to present your bag for inspection or not, no employee or manager can touch you or your property unless you give them consent to do so. If you do choose to comply with an inspection request and a staff member asks you to move items in your bag, you can still refuse that request. If a staff member/manager DOES touch you or try to restrain you, request that the police be called as that person has committed an assault against you (unless of course they have in fact witnessed you stealing and you have said property in your possession).
One case I attended was when a customer did indeed take a store manager to court for assault & unlawful imprisonment, when the manager forcibly restrained them and took them to his office under the allegation of shop stealing after refusing a bag check. When police arrived they found that the manager could not identify what the customer had supposedly attempted to steal (the customer had not made it out of the store), but said he believed the item was in her handbag. The police requested the customer allow a search and found no evidence a crime had been committed. They had to request the search as there was no legal basis to demand one - the manager could not identify what item was stolen, just a general allegation that she had something concealed in her bag. I could be wrong but I believe in some jurisdictions the police authority to search has been broadened now.
They asked the customer how she wished to deal with the situation wanted to deal with the situation, and naturally she wanted to press charges. The company lawyer in court brought up the conditions of entry sign as part of their defence, which was rejected. The customer’s lawyer brought up a few giggles though when stating that if the sign said “You must remove your pants or skirt whilst shopping here” would the store manager have thought it ok to attempt to remove the customer’s clothing.
TL;DR
You have the legal right to refuse a bag check, or refuse to move items in your bag if you have consented to a bag check.
The manager/owner has the legal right to deny you future entry on that basis
Unless you are in the act of committing an offense, no staff member (including store security & management) has the legal right to touch you or your property, or detain you in any way
All the above is based on my experience in the industry and the courts, and could have changed since I left - I am not a lawyer so if you decide to play hard ball, check the current laws in your jurisdiction first lol. Assault & Unlawful Imprisonment have not changed though, they are long standing laws which they’d find extremely difficult to change lol.