I have pads to prevent scratches. I will try to hang it on a door, but that's not always possible. If I don't hang it in an obvious place, then I make sure to put it's location in the agent showing instructions. 

The front door if they have a screen to cover from street. Railing on porch. I always make it known to the agent.  Have not thought of a pad behind for scratches.  Good idea.

Wherever it makes most sense. Often it is on the gas meter on the side of a house - out of sight ... and I always indicate in the MLS where the LB is placed. 

Front door.

Front door if possible; otherwise many of the options you listed.

The fornt door is the most convenient!

 Good morning Fred Griffin . For the most part, I see it on the front door. However I have seen them in places you would not imagine.

Good morning Fred. On all the homes we flip, the door closest to the driveway.

If it is possible, usually on the front door know Fred Griffin .

I try to hang it on a fence or a front porch spindle.  It's not totally obvious but easy for an agent to find.

front door with pad

try to always get it on the front door.

Pipes in the bushes.... Door knob is problematic and too visiable from front.

it totally depends on if the house is occupied or not.  Not occupied generally the door, but not always if it's occupied.

Our Supras are rubber so they shouldn't scratch.  I'll typically put them on a water pipe, front door as a backup.

I hang it on the doorknob or a porch rail near the front door. Never have I hung it on a gas meter, gate or faucet.

Ideally on the front door with a pad.  If not possible, as close to the front door as possible

I want it somewhere easy to find for an agent but not visible to a crook. Usually a hose bib.

It varies, but mostly on front door. I have one now on shutter hinge on a covered front porch. Sometimes sellers want it so it's not visible from the street.

Fred - Our Supra lockboxes are typically hung on the front door if they can be. Secondly, they will be hung on the gas meter, or a hose bib on the side of the home.

Fred,
I prefer a rail or bench. Faucet is my last choice.

90% of the time it is on the front door.  Some door handles do not allow this, and on occasion I have to find a different location.  Sometimes on the gas meter, railings or the light.

we never put them on the front door usually the gas meter or hose bib on side of house.

It depends.   

Sometimes have a pad.  Sometimes not.  

I try to place it not on a door knob to facilitate entry to the home.  Hose bibb, etc works fine

where it is visible and will not do damage!

Fred Griffin Front door when possible.

Anywhere & everywhere. Mostly front door inside the storm door.

Water pipe, gas meter, tree in front of house hidden with leaves.

Front door

I put it in the door we are going to enter. I do not put it on a faucet as i have seen them ripped out. All my boxes have pads

Always on the front door unless it doesn't fit somehow. Whether I pad it depend on the door. There is nothing worse than having to tromp around a property (sometimes in muddy situations) looking for a lock box and then tromping back to open a door. For my listings, my thought is always to make it as convenient as possible for a showing agent and her/her clients to enter a home and look at the home instead of futzing around looking for a key box.

A secure location is important. I try to cause no further harm to a property. Sometimes it is tough to find a good spot.

Most of the times it is a water/gas pipe for a single house and designated space for communities. 

I do wish they would find a better place for them than the door; very hard on the knuckles and the door

I try to stay away from the door knob because it makes it harder to open but that beats an exposed area where in bad weather it discourages showings.

The first choice for a Lock Box is a door knob or screen/security door, with choice number two being a gas meter Fred Griffin.  If the location is out-of-the-way, meaning not easy or typical to find, we will leave a comment in 'Agent Only Remarks'.   

I often hang it on the garage service door (if there is one ).

Fred, this is quite reminiscent of Dr. Seuss!  I usually hang mine on the front door or close by on a railing.  If that doesn't work, it'll be a side garage door, a faucet would be my last choice. 

I place it near the door.  I do not put it on the door knob.

I hang it on the door and do use a pad to stop scratches unless I use two lockboxes, then I use a Bicycle chain to hang the both either on a knob or around a picket in the front porch.

Usually the gas meter, a common spot in our area.