if superman or spiderman existed in real life, our government would know in just a few days who they really were. all that they would have to do is record the hero's voice, then run that for a match against the trillions of recorded phone calls the nsa has on file - literally every single phone call made from or received by any phone carrier in this country. they already have the software to do so - the documents that edward snowden leaked made that clear.
from there, they could pull a photo or video of the hero in their civilian clothes from their phone or any of the millions of traffic cameras, which they could also use to tell where they were at any given time, because they have facial recognition software now, too.
but, since superheroes are fictional characters, all that the nsa, fbi, cia, and other spy agencies have to look at and listen to are you and i. every minute of the day and night - even on christmas.
these are the things i think about when i walk my 10,000 steps.