[Snowflakian]

Depends.

To an extent it is possible they already do exist, just not in the same form as the ones you see in heroes or read in comics. The world is a massive place with oddities showing up all the time that are capable of outside of the norm things.

But in a Heroes/X-Men scale... I'd think of it still as I do any person now, but sadly the world as a whole would react much like the prison scene in Heroes since the tech for sentinels or similiar is a long way off from existing. At least in that scope. The reaction would be much like what's seen at the end of X-Men First Class.