I really don't like keyless entry systems - you know - the key fob that isn't really a key, but is a wireless transmitter that talks to the car based on proximity. I'm talking about the passive ones that allow the doors to unlock when you touch the handle. Inside the car they typically replace the ignition key with a push button. They fundamentally break the centuries-old cause and effect cycle that humans have with keys, and that is this : key makes contact with lock, lock opens.
I'm not convinced that keyless entry systems are solving any particular problem. They do create trouble though. First, and most trivial, they're incredibly difficult to get accustomed to. Every time I rent a car with these things, I poke and scratch the dash trying to find somewhere to put the key. Then, realising it's a keyless system, I drive off and when I come to get out, spend a moment or two fumbling around the dash and steering column looking for the key again. Despite renting dozens of cars with this feature, I still cannot break that association.
I now own a car with one of these except mine isn't passive. I have to push a button on the fob to open the doors - OK I'm fine with that - but the ignition is wireless pushbutton. So - erm - what do I do with the key fob when I'm in the car? These things are not small - they don't fit easily in trouser pockets especially if you have a wallet in one and a cellphone in the other. You can't use the cellphone pocket - the phone gets scratched and messes with the key signal and the wallet pocket is full. Shirt pocket? Not really - they're too heavy. Leave them in the cup-holders perhaps? No because then you will forget them. If you're a woman (or an 80's guy with a man-bag) you can keep the key fob in your bag, which is certainly more convenient, but still not ideal. With the traditional ignition key, the key is inserted into the ignition barrel when you drive - you don't have to find somewhere to put it.
The next problem isn't so trivial - the proximity system is very insecure if your parking spot is close to your house (like in the garage attached to it). I've found most passive proximity keys have enough range that it's perfectly possible to open the door, get in and drive off leaving your keys behind. This happens once you've broken the cause and effect cycle, and become used to the idea that you no longer have to have the key in your hand to unlock the car. One day you will forget to put it in your pocket, and then you're screwed. Why? The keys are momentary, meaning that the car doesn't constantly query the key. It can't as that would kill the fob battery in a matter of days. So instead, when some critical even happens - starting the car, unlocking the door - that is when the car queries the key. After that, it's never queried again. So this is why you're screwed and how you end up on a tow truck: the place you keep your keys at home is close enough that the car can 'see' the key fob whenever it wants. One day you leave the key at home, go to get in the car and it lets you. Similarly you can start the engine because the key is still in range. So you drive off and the first time you stop the car and get out, you've cemented your fate. When you come to use the car again, you'll be on the phone to your other half, or the tow truck driver, because the key is well out of range - it's still at home. Worse - if it's a fully passive key, once the engine is off and the door has been opened and closed, it will likely lock you out too.
The extension of this issue has to do with crime. If you live in an area of high car crime, someone can steal your car without even needing the keys - then drive off and work on the system at their leisure somewhere else. That's not supposition - it's happened three times near where I live in the last year. The stories have been in the news sporadically.
Through empirical testing, I've found that Nissan's keyless entry system has a range of about 20m. Chevy's system works out to about 25m. Others I've tested sit in the mid-range, between 15m and 20m. That doesn't sound like a lot but for example if you're parked at your favourite fast food joint, chances of you actually being more than 20m away from your car are slim, so effectively, it's sitting outside ready for anyone to touch the door handle, hop in and drive off.
The only vehicles I've found that gets close to solving the problems of keyless systems are Citroën, Mini and some Audis. In their systems you have to place the fob in a slot in the dash for the car to start. That maintains the cause and effect cycle of keys in locks, which I don't think is a bad thing.
So far at least, I'm finding keyless ignition and entry systems to be creating new problems we don't need, and solving old problems we don't have.