I
In my younger days I have tested “security” and true they cannot grab a person, only LE can. I have walked right out the door with one shouting at me to halt. Following them back in to a back room is silly but many would.
That’s state by state specific. I worked store security from age 17-20. In Florida it is illegal to resist arrest from a store merchant. A store merchant has full arrest powers to detain a shoplifter. And can use force to detain a shoplifter. Same force a cop can use.
I have been in knock out drag out fights (always won) and got the handcuffs on. The cops came and charged them with resisting arrest and petit theft or grand theft.
Store policies have changed and most stores do not allow aggressive detainments like I used to do 20 plus years ago for obvious liability reasons.
It was a fun as heck job for a young kid that was in the police academy .