I know this is an old topic, but I'd rather drag it up than start a new one.
It seems to me that since the new patches, I've been disabled by this alert quite often. I'm not sure if anything was done to change the previous behaviour, but it's happening on average 4-5 times per week now and in the past it was more like once per couple months.
Perhaps HTC could make it so that if you turned off auto-trim after it freezes your controls, you'd regain control of the airplane.