I would say that they were sloppy but would get away with it because the alternative would likely be bloody. They could handle it without casualties and thus at best you would get some complaints from the guild about conduct. If they have to write reports this would not look great and probably keep them from ranking up as quickly or perhaps at all.
The damage was vague enough however that they might not make a big deal out of it. Once or twice against sizable threats is acceptable, just don't make a habit of it.