I agree and wouldn't go out on the road without an engine guard. In fact, I installed saddlebag guards on my SG, which didn't have them originally, for further personal protection and to protect the saddlebags in case I dropped the bike. I had a major accident last October when I hit a dog and other than a partially-torn ACL from bouncing down the highway had no major leg injuries, and the guards protected the engine completely from damage. All damage was cosmetic even though the bike slid 100' or so down the road on its left side.
As for cornering, the kickstand drags first on left corners only, then the floorboards. If you are really leaning into the corner they will pivot upwards and the floorboard brackets are next in line. They are fixed to the frame and if anything raises the wheel in cornering it will be these brackets. I've never heard of anyone scraping the engine guard in cornering, although I guess anything is possible.