The risk is from wounds that don't heal well if your blood sugars are too high.
I've been advised not to use the whirlpool/massage foot baths, and not to use various implements that might cause skin damage, ...
All, I understand, due to the risk of open wounds or skin damage that won't heal well. As my diabetes is in remission and my blood sugars always in the normal range this should not be an issue for me.
(I do have a risk from injuries to my feet as I have some non-diabetic peripheral neuropathy so don't always realise I've cut my feet and need to keep them clean.)