Not yet.

Of course, I did by many reasons.

And I would do the same in your situation. If the house is 'enter at your own risk', going there late without light does make no sense.

Usually, it is the house itself. Some issues can become liabilities: mold, holes in the ceilings and floors, the foundation ( houses on the hills), etc. 

Yes, we have one that we do not allow anyone into.

If I find the buyer ready, willing and able and willing to come into the office for an initial consultation, and upon qualification, I will show them any house as long as I take someone with me, let someone know where I am going and with who or take precaustions while I am there, I feel safe

Paul, one house had mold so bad that it was instant headache when I walked in through the front door.  I told the client it would be unwise to go ahead due to health reasons. 

Paul Henderson - you are just doing right - the buyer needs to adjust the schedule to look at the home.

There have been two very distinct times that something didn't quite feel right about a showing.  Both times I took another agent with me.  And, both times, I was glad I did.  It wasn't the neighborhood, or the house that concerned me. It was the individual.  It was back in my early years as an agent in the 1980s. Back then, we did a little prequalification of buyers, but didn't always insist they become lender pre-approved before showing.  The pre-approval process does add a measure of security.

My wife had an incident where she made an appointment to a very out of the way home.  When she arrived, the keybox was not out.  After checking out the neighborhood, it was out.  She called the homeowner, got voice mail.  She knocked, rang the bell and elected not to go in.  The owners boyfriend later called that he was "waiting for her and her client to come in and was going to let them have it."  She trusted her gut and I'm glad she did. 

I refused to hold open houses at a home that was in an okay neighborhood, but the street in front of it was a major thouroughfare to a bad neighborhhod. 

Decided I did not want to be a sitting duck for any trouble. That one was by appointment only.

It still sold.

Yes, As a lender I went to an open house with a Realtor.   She was the listing agent.  We walked in thru the back door.  It was a 'crack' house. We walked out the front door.  I advised the realtor to leave and never look back.      

I have refused to list a house because of the neighborhood. I didn't want to be in the area even in the daytime. 

Being a buyer broker for a home that was a short sale, ring door bell where the seller was there, yelling we were stealing her home by trying to buy it. We moved pretty quick to get out of there

Yes, but never because of the location, rather the home.   Either mold or loose floors that I was afraid to walk through.

In the situation Paul Henderson describes I would have known showing a house when it can not be seen (dark) is and exercise in futility. I would have refused.

One of the best listing I ever took compelled me to have all who entered to sign a waiver stating they have been advised of the hazards and hold harmless the agent, broker and franchise involved. The property needed a clean out and the real hazard present was to those wearing open toed footwear who were denied entrance anyway.

Everyone thought they were getting into a very special deal and the offers poured in and EVERYONE provided complete and real contact information!. I am looking for another property to execute the same plan.

I would have handled it the same way.  I tend NOT to show past dusk.  Properties do not show as well, in addition to safety factors (personal safety as well as property safety).  "Enter at your own risk" also concerns me regarding liability issues..

Paul,

I was once showing a building that we were going to lease for short term, and as I was walking around the second floor, my heel went into the floor.  I got the potential tenant out of there, and promised to show him an alternate space.  Then, I called the owner, and told him about it.  We all decided to tear it down and build again...

As far as areas, since we were focused on hip luxury, potential places were often in decent areas, although we had bums finding a way to get in and sleep there.  A

As an older female, there are certain areas of town I don't work in. I don't advertise in those areas and would refer those buyers to a neighborhod specialist.