We recently sold our home in one day. Nine families and their agents came by one afternoon at 30-minute intervals to view the home.
We were present during the showing of our home, met all potential buyers and real estate agents, and answered questions posed to us. We had an formal written offer to purchase the very day the house went on the market - for more than the asking price and "as is" with no contingencies.
I guess some real estate agents don't want the owners present because they can "blow the sale" by giving too much information. That might be true in some circumstances, but we sold our house just fine.
About half of the real estate agents who came in our house did not know the neighborhood, or the most basic information about the property. We did not expect this, because our town is so small. We also noticed that when an agent did not know the correct answer to some questions, he/she made up an answer. Some agents actually made a point of listing the negatives of the house to the prospective buyers. We noticed that some agents arrived late and rushed their clients through the house. Our experience may have been the exception, but the only people who seemed nervous were the agents. Most agents seemed angry that we were home. The professionalism of the nine agents in our house that afternoon varied widely. Some were friendly, helpful to their buyers, and knowledgeable. Others were not. Other agents kept us busy with small talk while their clients explored the house.
Prospective buyers asked a lot of questions about the neighborhood and the house. Some did not like the paint colors in some rooms, and others did not like the shower in the downstairs bath. Others asked about the large dog next door, and still others wanted to know about the hiking trails behind the house. The people who did not like the house gave us clues as to what we could do to spruce up in some areas, or make changes. Very revealing experience, and interesting.
We do live in a very competitive housing market. It is a "sellers market." Maybe the standard rules don't always apply when people are desperate to purchase a home.