checking if brake lights are working while in the car?

Because if you had to suddenly use the brake, you couldn't.

Am I missing something here?
The original suggestion was...

I was told to say park the car in a safe place and wedge something on the brake pedal and go check.

Why would you have "...to suddenly use the brake..." in a parked car?

As a suggestion to answer the original question you could ask for assistance from someone else...
 
Am I missing something here?
The original suggestion was...



Why would you have "...to suddenly use the brake..." in a parked car?

As a suggestion to answer the original question you could ask for assistance from someone else...

My original question stated :
"while in the car on your own"
 
could garage forecourts have a white reflective sheet or similar on a blank wall so if you pulled in and turned away from it and braked you could see if all your lights were working? I sometimes reverse my car into the drive and try and check on the house wall if they are showing. but its not ideal.