Engine oil, coolant, hydraulic fluids and general lubricants should be drained at working temperature to ensure that contaminants are in suspension so they may be cleaned from the engine with emptying of the bulk of the contents. Normally this can be a dangerous operation and so it is usual to let the engine cool to some degree of acceptability before handling liquids. The problem with is as the engine cools the contaminants drop out of suspension in various places leaving dangerous materials within the internal structures.
Hot liquids are dangerous!
With a sump running an ADP fitting, the hot oil is contained so that it can be safely drained without contact. The dust cap will be hot but dry and is easy to remove by hand or with tools. The drain tube may be screwed onto the drain plug before the heat is transferred. Prior to fixing the drain tube, the outlet end should be positioned into the receiving container. The container may be an ordinary oil drum or other container with a small inlet hole. A small inlet hole reduces the splash normally associated with oil changes.
The ultimate oil change system would include a suction system and an oil delivery supply via the ADP drain plug. The oil then would be entirely enclosed at operator level.