Things are not always the way they seem; people are not always who we think they are. That’s why we never judge a book by it’s cover. Take the time to find out; take the time to ask so you can know for sure. Never act upon assumptions. Act on what you know for sure.
The Israelites almost started war with the very brothers who had stayed to help them conquer and receive their alloted land. All their service could have ended in unwarranted death due to false accusations.
It’s great that they took the time to ask. Thank goodness they never acted upon their assumptions.