Tom, I've read about that same procedure being used with a Westinghouse, and has been mentioned, there are holes in the insert and pegs in the roaster body designed to allow for this. And yet instructions advise against ever using the roaster without the insert placed inside the roaster cavity.
Even though the cavity is water-tight, I would guess that the only uses with the inverted insert on top would be for things that weren't being cooked in any liquid. If I were ever to use a roaster this way, I'd try to find a roasting pan that fit inside the cavity (with enough space around it to easily extract it, of course) to collect drippings, etc. and possibly effect an easier cleaning process after use.
Certainly the amount of energy required to maintain temperature for double the volume of heated space would be significantly higher, causing the heating element to cycle more often, and the inverted insert would be a burn hazard in the event of accidental skin contact. A manufacturer's suggestion for this procedure would surely be DOA with the CPSC today, even if they included an insulated wrap for the insert to remediate the risk of injury, I suspect. Everything must be idiot-proof and plastered with warnings like a sun visor in a car.
Even though the cavity is water-tight, I would guess that the only uses with the inverted insert on top would be for things that weren't being cooked in any liquid. If I were ever to use a roaster this way, I'd try to find a roasting pan that fit inside the cavity (with enough space around it to easily extract it, of course) to collect drippings, etc. and possibly effect an easier cleaning process after use.
Certainly the amount of energy required to maintain temperature for double the volume of heated space would be significantly higher, causing the heating element to cycle more often, and the inverted insert would be a burn hazard in the event of accidental skin contact. A manufacturer's suggestion for this procedure would surely be DOA with the CPSC today, even if they included an insulated wrap for the insert to remediate the risk of injury, I suspect. Everything must be idiot-proof and plastered with warnings like a sun visor in a car.