The disadvantage of tucking it into the belt as DoctorMike pointed out is that it can slip out. The advantage is that there is a one step, one hand donation process. You donate the regulator and it can just pull free without the light cord/long hose crossover confusion. My NACD cave instructor preferred this location despite wearing a can light for that reason. If you don't dive often and don't practice S-Drills enough, as some recreational divers don't, this might be the preferred location for simplicity in an emergency.
Using a scooter will most likely result in the hose pulling free of the waist belt. Lots of water hits the hose and the harness gets pulled by the scooter. Wearing the hose behind the can light keeps it relatively tucked in place. Occasionally, the hose will pop out from behind the can, but not frequently. The donation process becomes two step. Donate the first part of the hose. Find the bit that's tucked behind the can and pull it free. If you don't pass your light cord underneath your long hose, then you also have to deal with a light cord and long hose cross. It adds a third step in an emergency. You run the cord under the long hose while the drill or donation is underway then over the long hose once the drill or donation is over to clean up.
They make a little delrin rod that looks like a small police night stick or billy club to hold long hoses. Some people like these, but I'm not a fan of equipment that serves only one purpose on the rig. Recreational divers may want to use something like the Halcyon zipper pouch to hold items they may need rather than clip them to D-rings or wear pocket shorts or have pockets installed on wetsuits. If you are a wreck diver, an extra cutting tool such as a knife or scissors with enough protrusion to hold the hose may be preferable. Cave divers prefer tucking the hose into the waist band if using a cordless light. There is nothing else that needs to be added to the right side. Any item like a long, stiff knife or a derin rod can become a potential snag hazard if trying to back out of a restriction.