Rubbish - sorry but there is absolutely nothing wrong with an electric blanket.
The inadvisable ones are ones from carboots which are 20 years old and have dodgy wiring.
If they were really dodgy, I doubt you would find Debenhams, John Lewis etc selling them in this age of litigation.
We used to use one - unfortunately since we went up to a super king size bed we can't get one that fits. There is no nicer feeling in winter than getting into a prewarmed bed.
I do agree - DON'T BUY A SECOND HAND ONE though.