You might be surprised by the semantics assigned to double clicking the button by some manufacturers. On some BMWs (mine included) locking it twice DISABLES the alarm. It's intended for ferries / low-loader recovery etc. but if you don't know it...
The lock button on a BMW is completely driven through the CPU. When you lock the car with the remote, the lock buttons inside the car AND THE DOOR HANDLES do nothing. Anti-theft measure I suppose.
Salesmen have to remind every new customer about this, since sooner or later someone locks themself or someone else in the car and the remote has walked away...
VWs can do a thing where the windows open if you hold the lock key down - fortunately this can be turned off in the cars configuration settings for people who live in rainy countries!
