Stopping a concret block wall falling over...

At one place in my yard, I have a 3' drop down onto stone. I am planning to put a 3' high wall, made of 4" concrete blocks, along the edge of the drop - to stop people falling into it.
I can tie one end of the new wall to an existing wall, no problem. The wall is only going to be about 2 1/2 blocks long and will be built on a concrete base. But I am worried about this wall possibly being pushed over - perhaps even onto a child that might be on the lower level. Murphy's Law and all that.
So what I was thinking of doing is put a reinforced concrete post up at the far end of the wall, sunk into the concrete base, and tying the end of the wall into that post, at every course.
Do you reckon that is good enough, OTT, or what?
It doesn't have to be a block wall - but it has to be 30 minute fire resistant, for other reasons.

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