You shouldn't let your hair get caught underneath your processor. Before you attach it, make sure your hair is not in the way.
I'm not in the habit of running my fingers through my hair, but I haven't had my processor "pop off" since I first started wearing it over 3 years ago - and it didn't really pop off. It happened twice; once when it encountered the door frame of my van and the other time when my son was waving his hands around wildly at dinner and I was sitting next to him (he inadvertently hit my head).
My best advice is to get out of the habit of running your fingers through your hair when wearing your processor - probably a hard habit to break if you've done that for years. Or, you can wear the "fishing line" as Ken suggests.
Either way, I'd do something. It's not good for your processor to fall to the ground. Although you say it hasn't been damaged, it could have damage you can't see. Or it may be fine now, but a few more falls to the ground could damage it. You also face the possibility of something happening to it when it's on the ground - someone stepping on it, etc.
Your processor in an expensive investment - even if your insurance company paid for it (because chances are they won't pay for another for at least 5 years) - you need to take care of it.
Feedback issues are normal when your processor encounters a solid object - back of the couch, your hand, etc., - but you may be able to have it programmed to ignore most, if not all, feedback. For example, I can reach up and touch my processor without it making any noise; it's all in the way it's programmed.
Jan