I wish to improve, and this is why I reacted poorly on my answer being deleted. I've read the "no theoretical answers" several times, but one thing I find odd is that several are still accepted. If a question can not be answered completely, such as "research indicates but does not prove...", it's theory. Yes, I get some may pass for various reasons, but I am more interested in the thought process here. Even more on why my question is marked as unaccepted.
I provided sources, some vague, but the question came from a myth, something that rarely provides enough, finite evidence. Conclusion is actually finite. The fact HDD's need strong magnets to even get affected is evidence 1, source indicating the magnetic fields in the subway may be lower than what you'd find occurring even natural at specific points was evidence 2, leading to conclusion that no, there was no danger. I wrote "extremely unlikely" as a kick to the fact it was based on a myth, and a vague source for the magnetic fields in subways. What I should have written there was of course that global location of subway may make the values vary from what was provided in the source I linked.
In short, what I ask is why I got no warning, such as "better\more sources" required... I wish to know what made my answer seem theoretical.