Yea, what stealacandy said.
Untill he began teaching, he could get away with it.
Would (again) give Dumbeldore(?) some bad press.
And best of all, blow Lockharts hero bubble. :p
Harry can/could start with giving away a copy of his book list. ;7
Hope you can give Sirius a real trail or atleast giving the press the clues needed to start digging.
ps: JKR's main press could just be the biggest since it's gets goverment money to spread their words.
The Lovegood's their paper could be also handeling muggle things in a wizarding way. :D