Zeeb,
There is more than one Fail safe in the Spektrum radios.

Take your DX7 using the updated AR7000 with Quick Connect feature. Put the RX in Bind mode, remove the bind plug leaving the light flashing, put all controls in weird positions where they might go in a programmed failsafe. Turn on the TX while holding those positions until the bind is complete.

Then do your test. Turn on everything, turn off the TX. see what happens. Only works when you have the quick connect programing.

I know it gets confusing until you get your mind wrapped around the idea that it does way more than one failsafe. It seems Spektrum provides so many features that other radios can't do that people simply don't believe it. Subsequently it is confusing.