Correct; the API is only available if the campaign was created by a Mentor, and is only available to the campaign creator. I have a campaign running right now where I created it and have added API, but I promoted someone else to GM and I run the campaign as a player, and it works well. I get glances at the top-left corner of the map when I load (which I'm not supposed to see as a player if it's hidden), but that's a small price to pay. One thing I've implemented in a campaign I run myself is an OOC room. After each game session, I move the players to the OOC room, and they can play with their character tokens and draw all over the map as they please. When everyone has loaded into the game for the week's session, I move the players to whatever map we're going to be playing on, so everyone starts off on the same foot.