Incidentally the blanket exemption in Canada allowing the use of MDA as DA (without adding 50ft) will expire at the end of this month -- April 30, 2015.
Thankfully.
Most have no concept of the difference, nor how far above MDA their actual DA is (it sure as hell isnt 50 feet, but at least the 50 feet + ROC gives some hope, and hopefully most obstacles are in the missed)