I have never seen a direct report where gimbals were stopped at the gate. So long as you don't have an extension arm, I'm going to guess you are OK. I did not get my Osmo in time for my last trip, but I have seen several reports here and elsewhere where they were allowed without question. I had my Feiyu (which looks very similar to yours) for my Hero and I just never pulled it out of my bag. I meant to but it just never happened.
In all fairness, we drive to the parks so it's a lot easier for me to take mine back to the truck than it may be for someone else to get back on a bus and take one back to a resort, however I believe that would be a moot point based on my readings. I don't think you'll have any problem and I fully intend on making BIG use of my Osmo on our next trip coming up soon.