I had a problem - I'd lost the keys to my black Spider, just a few weeks after buying that car. This is a particular achievement because it came with two red remote keys, one red valet key, and the 'bordeaux' red (brown) master key. The full set, in other words, and I'd lost them all.
After some time searching the garage and the living room, I eventually found three of the four keys - but the remote key wasn't the remote key I'd been using and didn't work. I had to unlock the door with the key in the lock, start up, and drive it into my garage with the siren blaring. Quite embarrassing that the factory alarm keeps going off even after the engine is started
Next I pulled apart the remote key that I'd found and got it working with the usual trick of cleaning/resoldering the switch inside.
I was saddened that I'd lost the other key (plus my house key), but life went on. I should point out that my yellow Spider came with ONE key and I never lost it in nearly two years.
Then a month later, I was out in Cambridge (22km away) at the workshop of my friend the FIAT and Alfa specialist. Just inside his roller door is a shelf with all the keys for the wrecked cars and various other cars parked around the place. Lo and behold, there were my keys! I've never been so happy
I'm sure I didn't put them there, but must have put them down somewhere else.
It does leave the small question of how I drove home after leaving them there. I think I must have taken them in my other car to use as a house key, but then accidentally left the garage door remote in that other car so that when I got home, I used the door remote, and didn't think "where is my house key?" since my garage has internal access to the house.
I guess what I'm saying is that if you have multiple keys, you WILL lose them
If I'd had only the one house key and no remote, I wouldn't have lost them.