Interesting, but is it practical to try and protect every table in this way?
In case you are interested - and I am not suggesting this is any better, but for someone like me who works on "other people's systems" it is an occasional watchdog - I have an addin for SSMS 2012 that will alert you if you run a sql statement which updates or deletes and does not include a where clause.
It does not pretend to cover anything other than that simple check but I find it makes me smile when I see it pop up - it just makes me stop and think "do I really want to do this update?"
See my signature for "MMNose" (the name is because I plan to expand it to "sniff" out other bad smells)
MM
select geometry::STGeomFromWKB(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