Normally I'm in favour of folks using high levels of force to defend themselves, but it encourages the spread of HIV, and that makes it abhorant and wrong. And before someone makes a a comment saying that it's only those breaking in who would be affected, a) you can't guarentee that no-one will make contact with it by accident b) even with the warning, it is still an unjustifyable risk to emergency services and the like even with the warnings, and c) someone (criminal or not) might not realise that they are infected and spread the disease further, meening an inocent might still be affected.