Is It necessary to double lock the doors when I park in a dubious area?

 

Not sure what you mean by double lock, but I only push the lock button on the key fob twice to turn the headlights off to shorten the time they are programmed to stay on.

 

There is no such thing as "double lock." The doors are either locked or unlocked.
The answer to your question is clearly "no," it is not "necessary" to do this in a "dubious" (dangerous?) area; it might be wise or prudent, but it's not necessary. It's probably not even a state law.

 

To the OP? Did you have some deadbolt installed to your RX? Wow that's some customization you got there.
Seriously, one click of the remote or one click at the door handle will do the job.
If you're really concerned about a specific area, then don't park in that area or have your thumb glued to the panic button.

 

I know on a Honda, first click will lock all doors, and second click will "Beep" the car. Still no difference what so ever.
Not sure what OP is talking about.

 

Custom deadbolt lock FTW.

 

As DunWkg have mentioned. We double click the lock button to shorten the time that the headlights and the courtesy lights are ON.
I for one leave the DRL to Auto so when I exit the vehicle and just click the lock button once, all the doors will be locked, the alarm is activated but the lights are still ON for about 20 seconds.

I hope that explains the purpose of the double click.

 

Sorry - was reading a non-usa 450h manual where it states the following:

Theft deterrent system:
Unathuorized access to the vehicle is prevented by disabling the door unlocking function from both the interior and exterior of the vehicle.
Setting the double locking system:
Turn the "POWER" switch off, have all the passengers exit the vehicle and ensure that all the doors are closed.
Using the entry function:
Touch the sensor on the outside door handle twice within 5 seconds.
Using the wireless remote control:
Press 'lock" twice within 5 seconds.
CAUTION:
Never activate the double locking system when there are people in teh vehicle because all the doors cannot be opened from inside the vehicle.

 

I try not to park the car in a dubious area. If we have to go to an uncertain place we take the jeep. My other definition of dubious is a parking lot where I am most likely to get dinged. In this case I park the car as far as I can away from the main cars preferably at the end. A lot of people don't care when they open their doors.