If you put a toaster beside your bed, I'm 100% sure it will go up in flames O.O If you put a heater right beside your bed, then your bed will catch on fire. If you set any blow-dryer onto your bed, your bed will catch on fire, and you may end up with tons of burns on your face.
But if you just block off both of the sides of your bed with whatever that's not fully-electric, then nothing bad will happen ;)
If there is a fire in your room, you can't block the fire from burning anything. Fire will really burn or melt anything. It's best to just get out of your house.
I think it depends how and why. If it's done with newspapers piled to the ceiling, then yes, that would be a fire hazard. If it's done with guard rails designed to help a person with memory issues and/or mobility problems, then no.