To commit a criminal offence, one needs the criminal act (actus reus) and the guilty mind (mens rea). If someone deactivated the security system (actus reus) with the intent (mens rea) of helping someone else burglarize, that would definitely be a crime. However if someone deactivated the security system and without criminal intent helped a criminal, then it would be a much murkier issue. Most countries have various offences on the books for criminal negligence to deal with this situation.<p>On the other hand if the homeowner or the insurer wished to SUE someone for disabling the security system and thereby facilitating the loss of property, that someone would most likely be fucked. Civil liability doesn&#x27;t require the accused to be the sole cause of the damage; one can be a contributory cause and still get roasted for huge damages. 
<i>IANAL and this comment is not legal advice</i>