It is possible to remove these bolts but as above you need patience and care. I have been known to use a "nut spliter" to cut the nut off and then remove the stud afterwards. if you try to remove the nut and stud in one you will almost certainly break off the stud in the head which will lead to swearing and tantrums!
I use a thermal coil tool on really stubborn nuts and studs, works most of the time but can still snap off if your a gorilla.