Ok, I'll admit I live dangerously. I have used my microwave and AC (not together) even when the shore voltage is around the 100V mark. Successfully.
I know it is considered harmful to do so. Microwave and AC are the most susceptible to damage by this. Most other things; not so much. Electronics (computers, TVs, etc.) are completely safe to do this, as are lights, toasters, coffeemakers, etc. No problems yet in my 10 year old camper (but I don't do this every day.)
I see low voltage very often in camping. I think the cost for most campgrounds to upgrade to proper wiring is prohibitive for many.