The odds that another player will report you because of the golden heroes are the same or even lower for higher ranks. On rank 20, you will face 80% noobs, 10% other botters and maybe 10% real players, who want to farm easily with there good decks.

The risk getting reported is much higher on higher ranks due to the increasing number of bether players who may get suspicious. And maybe 10% of these players have to the time and the passion to realy report you. I guess most of them try to chat with you or send you a friend request.