Not only this but many cars of the same make had very little variation in their keys meaning that on a dealer lot or even a very busy mall there was a chance you could unlock or start; rarely both; a car other than your own.
Personally I had seen this twice in action. First was back in the early nineties I could unlock my friends Escort GT with my key and he could unlock my EXP. Neither could start it. Now my Aunt and Uncle had a Ford Windstar and Mercury Sable. The Sable key could start the Windstar but not unlock it. My Aunt found this out the hard way after a trip to the store where she could not get back in the car.
Now my BMW motorcycle uses a keyless ignition but you have to stand so close that I am not sure how well the hack will work. As in close I mean nearly rubbing up to it and only from the left side, from the right if they key is in the pocket away from the bike it won't recognize. There is an emergency key which is an little plastic type that has no power of its own, you can start the bike provided you find that magical point near the dash it actually works; by that I mean it took me and the dealer five minutes to get it to work
Speaking from experience (locksmith), you cannot download the skills required to use a slim jim. Well, you kinda can, being that there are books/catalogs that show you where the lock's internal mechanism is, but being able to manipulate it requires more than simply pressing "exploit car radio".
I never had much problem breaking into my old 80s Toyota truck with a clothes hanger back when I was a new driver who would occasionally lock himself out of his car, but valid point - I know 90s cars especially made it a lot harder.
The wireless bit does seem like a big regression over non-wired digital security, though.