Answer:
Time wastage and not formal enough
Step-by-step explanation:
He didn't have to wait till that time to ask the the question, besides keeping them there will cause uneasiness between the workers because it's already late.
Another point is that some people might not decided to give him the reply face to face, as they night sound rude or something more than that.
A more formal approach and less time consuming and less stressful method like may be filling of forms, papers , or complaint letters should be used instead.