As I said in my last post, this was not "shoplifting en masse". I used that phraseology deliberately because several contributors either also did, or gave the impression, that they believed that that offence had taken place.
However, from the details given by lovemybabas, she has not actually committed a theft. Believe me, I was in law enforcement for 17 years and dealt with many shoplifters, i.e. people who had physically stolen items from shops/stores without paying. The same criteria has not been met here.
She was perhaps naive to allow her child to eat a banana prior to paying for it, but that in itself does not constitute theft. Especially as she also offered to pay.
Had she, though, just left the premises without making any attempt to pay, then technically a case could have been made out for theft. But that did not happen here.
None of us can judge what or what not was in the poster's mind, but based on the version given, which is what we're meant to be commenting on, no offence was committed.
Annoyed though the store manager may have been, could he not under the circumstances just have insisted that she pay for the banana, which she says she intended to do, instead of having her ejected? He exceeded his authority.
There are ways and means of dealing with situations and the manager, from the details given, made a poor decision. Had he felt that this mystical "theft by consumption" had occurred, he should have had the Police attend. His own authority does not extend to deciding what offences, if any, customers may have committed.