The Neighbors' Flowers Revisited

Last century, when I was married to someone else entirely, my then-mother-in-law visited from The Old Country. One day I came home from work to find a large, lovely and huge boquest on our dining room table.
"Where did you get these?" I asked, "They're great!"
"Oh, I went for a walk," she said, "They were all over."

By "all over" she meant "in the yards of other people". I never figured out whether she genuinely did not realize this or just didn't care.
Today, I was reminded of this event when I saw someone in the parking-strip garden of our neighbor's. An elderly woman and a tiny girl were picking flowers. These aren't just a few extra blossoms on the profligate butterfly bush, but a significant fraction of the blooms on flowers that had been individually planted.  I immediately challenged them and they hurried off. "Sorry, sorry" the lady said, but I didn't want to let it go at that. Her behavior didn't look like an honest error, and it was hazardous to boom; some people would react very badly to having a stranger take things from their yards, so it's not a good idea to have children involved. It looked from her guilty departure that her main mistake was that she did not plan on being caught. However, when I repeated to her something like she can't be doing this, it's bad, she replied, "I am Catholic".
The sheer incongruity of that reply stopped me as much as her having lumbered away. She clearly knew she had done something wrong, and I don't think we'd be seeing her again, so that was not an issue. I do wonder whether she was flustered or, more likely, was trying to justify herself as a good person by pointing out that, after all, she had a religion.
It can be difficult to know what to do in a case like this; obviously the thieves had to be sent packing, but perhaps a gentler verbal approach would have been just as effective. I reacted rather quickly and while I'm sure the outcome would have been the same in any case, I suppose there was a distant possibility that they were picking flowers with authorization.
Strange it was, however, to see the same thing happen after all these years!