There hasn’t been any mention of fridge work, but I will throw this into the mix.
One needs to be very careful about insurance, liability, dead mileage and demurrage (if you can get it! 
) Perishables raise many potential problems which need to be sorted before loading, because most of the time it is going to be the haulier who carries the can unless it is otherwise contractually.
Who is responsible for supplying fridge diesel ? - normally the haulier. Who is responsible for fridge breakdowns if the trailer is hired or the property of the consignor or clearing house? More importantly, who is liable for a spoiled load resulting from a fridge breakdown if the trailer does not belong to the haulier? - again likely to be the haulier.
Now to the more likely events. The outbound load is rejected for some reason. This is going to involve time and mileage, either to bring the load back or to wait while attempts are made to sell it to someone else and then deliver it to another location. This needs to be chargeable and understood to be so before loadiing. This becomes even more important if this is a backload and the consignor wants it returned.
Part of the load is rejected, but there are still other deliveries on the vehicle. A bigger problem because the inevitable delays this will cause may result in missed bookings and possible rejection of the remaining perishables, with a claim looming for their value aimed at the haulier.
There is an excessive delay at a delivery posing the same issues as above. Easier to deal with if the load is all from one consignor, but a big problem if it is not.