when using the crane to load cargo it is possible to keep the load attached to the crane while switching truck and thus bypassing the warning message preventing doing so.
How to reproduce:
-Attach cargo to a crane
-Open the map
-Chose a truck then switch
After that if you get back in the original truck with the crane, the rope from the crane will be invisble and will have a tendency to auto attach to any object near by, to see it again it is necessary to cancel advanced menu enter crane menu again.