Maybe im misunderstanding here so i want to ask a few questions to clear it up.

When backing up i have the Tandem 4 wheel disk brakes on my trailer. I use the standard 7 pin with the electronic back up circuit.

I also have the key for the tongue on a short cable and it plugs in right behind the ball on the tongue.

I was told when trailering to leave this key in all the time. It allows you to back the trailer up. I was told if i take it out the brakes will come on and you cant back up the trailer.

I always leave this little pin in the trailer, my driveway is very step, so step i only have 1 inch clearance under the cross beam protecting the prop.

I understand if im going down a ramp in reverse the brakes wouldn't be on due to the trailer pulling the truck down the ramp as well. What im wondering is if you don't have that pin in the trailer wouldn't you have issues backing up normally? Wouldn't the tongue compress just the same as when applying the brakes?