Which of the following is not a sign of concealment in a trailer?

The option that indicates a lack of signs of concealment in a trailer is identified correctly. When a trailer is mostly empty of cargo, it does not suggest concealment; rather, it can indicate that there is less likelihood of hidden or suspicious items. In the context of trailers being used for shipping, concealment typically refers to efforts to hide cargo that may be illegal or unregulated.

In contrast, the other choices suggest potential concealment. For example, cargo that is stacked sloppily might indicate that items are being hidden or packed in a way that obscures their true quantity or nature. Similarly, shipping company labels not appearing on all boxes could suggest an attempt to obscure the origin of the cargo. The use of generic or U-Haul boxes can also signal that an effort is being made to mask the contents, as these types of boxes do not provide identifiable information about the cargo. Hence, the overall assessment leads to understanding that a mostly empty trailer does not align with typical concealment behaviors.