Yeap, looks like it's for real. I'm all for having a hari for fan to celebrate the buku and/or JK Rowling, but 7 menit of silence?!! I agree with cassie-1-2-3's link on that one: it's disrespectful towards real victims of tragedies and wars.
Something a bit lebih Harry Potter related should have been picked to do on the day. I like how fan of Douglas Adams have Towel hari - where fan are encouraged to carry a towel with them on the 25 of May, because according to the Hitchiker buku a towel "is about the most massively useful thing an interstellar hitchhiker can have."