Sure agreed if they didn’t know, but it seems like there was at least a Hamas cell inside the UNRWA that did:
Inside one of the UNRWA buildings, journalists saw a room full of computers with wires stretching down into the ground. Soldiers then showed them a room in the underground tunnel where they claimed the wires connected.
Well to use your analogy here, let’s say a weed grow operation steals your electricity by plugging extension cords into several outlets and running them through open windows. Further let’s say this goes on for years with you living in the house. At a certain point it strains credulity to believe that you aren’t in on it.
Something similar seems to have happened here. It doesn’t implicate the UNRWA as a whole, but it certainly raises questions about the employees at this location.