I've never encountered a community as poor at cost/benefits analysis as computer security.

As the potential cost of attempting murder involves the risk of getting caught, it's entirely reasonable to expect murderers to go to great lengths to conceal their actions, even if in involves highly technical means. If such highly technical means are actually inexpensive and widely available, then this raises the level of concern with regards to the cost/benefit analyses.

In short:

Cost factors "pro" murder through wireless control of medical equipment

    - getting caught is very expensive, so obscure and 
      invisible methods are attractive.  
    - time and materials costs are low for a suitable expert
    - the method enables an alibi