There is that very, very, very, remote possibility, agreed. However, in the UK the overwhelming majority of modern houses come with composite doors and highly secure locks such as ABS, which are all but immune to lockpicks, crowbars and even police "battering rams". There are equivalent windows too. Also a lot of people have video doorbells and security cameras. These measures tend to deter almost all burglars/housebreakers/rapists and murderers. Were she to retrofit these items to her home, they would still work out cheaper than a gun and ammunition, secure storage and necessary training.