Yes, they are correct. The main problem I have with the regenerative braking theory in the context of our setups is that not a single controller that I know of makes any provision for setting the exact battery chemistry type and cell count or even warns about the use of lithium based packs if motor braking is used.

If ESCs are performing regenerative braking they need to warn users about how to configure their product correctly to accomodate their battery chemistry under braking conditions. Anything less is a serious danger!