Gents, I've posted this before. It's not a new issue, keys eventually fall out of these ignition switches. Kinda like leaving lottery tickets for your bike on the road.
When it first happened to me (in 2001) it was a weekend where I had planned to put about 500-600 miles on that Sunday, and having left the first key "somewhere" on the road Friday night where retracing my steps didn't yield the old key- I was real nervous about using the second one, my last. I lucked out in a way that I don't often do, but after stopping at a few hardware stores one of them had a key blank that was the right length and width, but the depth (thickness) of the blank was a little too much. I figured why not have spend a couple of bucks to have one made and try to file a little bit off the thickness of the new key a bit? Well, it worked and there was an added plus, check this:
Find a good hardware store, or call ahead to the ones in your area that are "big" on key making. Ask if they have a key blank with the number HD 82 stamped on the left and x129 stamped on the right. If they do, bring your spare to them and have however many copies made onto the new blank(s). They're usually a couple bucks each or so...
Take the new key(s) back to the 'ol work bench and use a 1/4 inch dremel tool barrel sander attachment a leetle bit at a time on both sides of the new key, as evenly as you can (when you're sober). Stop often, wipe the dust off the key and try it in the ignition. Once it fits... then go just a tiny bit MORE. Just a little. It only takes about 15 minutes or so when done very slowly and carefully. What you'll find is that not only will the new key work- but it will no longer "lock" in place inside the ignition switch when the ignition is on!!! So now you can turn your ignition on- pull the key out- then clip it to your wallet chain (just like with older HD's)! Ride as long as you want without worrying about leaving keys on the road in random places. The only trouble is remembering to take the key off your wallet chain and shut the ignition back off when you arrive at a stopping point (I mean, before the lights wear out the battery (or somebody yells "hey you left your lights on" -that's embarrassing)).
I thought of posting a photo of what it looks like but then realized I'd be showing the key pattern for my bike's ignition switch to the world, lol. If you want or need a pic let me know and I'll try to figure out how to do it without displaying said key pattern, but for now I gotta get to work before I'm late. Hey- it will give y'all time to call the hardware stores in your area to see if they have that blank, should you wish to take the poor man's approach.
I can honestly say I've never had to stop at Eastern Mountain Sports for a carabiner, unless I was planning to actually climb, or repel, or steal the pink panther diamond again--- cue music.

Respect,
OHM
P.S. After eleven years I've still got the original ignition switch on my bike. I think this approach also helps that "vibration" thing that causes so many to have to replace their switches over time. Just a reasonable guess that I'm making regarding that tho'.