I'm not sure why, but no matter how long I drive a car with keyless entry it seems like I always hit the wrong button on the remote. I end up locking the doors rather than unlocking and I had a car once where I popped the trunk all the time.
A new design concept called the Pebble is a very simple device that you can’t hit the wrong button with. Rather than pressing a button, you simply slide the device to lock and unlock doors. The Pebble also has a trunk button for popping the trunk.
The only downside I see is that the thing is rather large in its current form. It would be hard to fit it into my pocket along with my wallet, phone, and keys. The three little LEDs in the triangle shape light to show you if you are locking or unlocking the door.