We have electric blankets on all our beds in the house and also in our camper. Never had a problem with one shorting out. Now .... we have had problems putting the blanket away for the summer months and then trying to find the cord again in the fall.... somehow, they seem to completely disappear ... they must go to the same place all those missing socks in the washing machine go to. We end up buying new blankets every now and then because of this. The old ones are fine, just no electric. This is the ONLY problem we've ever had with electric blankets.
In the camper ... they are WONDERFUL!
The last 2 we purchased have automatic turn-offs. After 8 hours they turn themselves off.