The way the owners showed up on the doorstep themselves leads me to believe they have contacted the guards previously and nothing done. So they had to take matters into their own hands and fair play to them.
Yes I know it's not exactly crime of the century but it's mean spirited and just plain theft to steal from a business trying to do something positive within a community.
If anything a call from the gardai might mark their cards so to speak that they are not getting away scott free and might just make them think again about doing something similar.