I think you could indeed call it a coincidence because it's exploiting behaviors that are not really a proper ABI, just emergent behavior based on implementatio

I think you could indeed call it a coincidence because it's exploiting behaviors that are not really a proper ABI, just emergent behavior based on implementation details. Someone working on the various operating systems could change those behaviors without knowing that they're breaking this thing. And they wouldn't necessarily be in the wrong to do so. Because it's not really an ABI.