This is a tricky post. I would say generally you can take your fanny pack on the ride with you, however, it also depends on the CM.
Hubby and I always wear fanny packs and everytime we go to IOA, we get different answers from the CM's. I would say 70% of the time we have no problems, we get on the coaster with our fanny packs on. And 30% of the time we have been told to remove them and put them in a locker. This is such a pain especially if there is a big line, you have to either both leave (and lose your spot in line) or get one in your party to put them in lockers. Getting back in line is a pain in the butt though!
The worst was during our last trip. We got in line (fanny packs on) and it was about a 20 min wait and we started talking to the couple in front of us. They warned us that we would HAVE to put our fanny packs in a locker. We told them that we just rode this ride about 2 hours ago with our fanny packs on, no problems! Apparently they were in line, got to the front and the CM told them they couldn't ride with their fanny packs (same size etc as our packs)
so they both went to put their packs in lockers and got back in line (this is when we met up with them). So we just decided to chance it and keep going. Well we got to the ride and the CM didn't say anything to us, so obviously these people got VERY upset and started complaining to the CM about it.
Funny thing is....we rode Hulk again later in the day and they made us take our fanny packs off!
I wish they would just come to a consensus and either take ALL fanny packs off or ALL fanny packs can go!
