My main concern is these devices causing bodily harm. The dishwasher spraying hot water at me is pretty scary. A flooded house isn't nearly as bad as being disfigured.

  My main concern is these devices causing bodily harm

That's a reasonable, genuine concern, and one that should require physical interlocks (not just software code) to guard against.

That's a good situation for mandatory safety codes (such as the FDA requirements for 2 physical interlocks on microwaves [1]).

[1] http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRS...

What about food poisoning when I make your refridgerator turn off?

A flooded house is effectively extorting you with threat of bodily harm, because it costs money to dry it, and if you don't dry it promptly then mold will grow, which will cause health problems.