There is a wonderful episode of COPS where a similar mistake occured. I think it was shot in Ft. Worth, but am not certain. The officer saw a house on fire, called the fire boys, and then proceeded to bang on the door and eventually breaking out several windows while shouting there was a fire. There was some very dramatic footage as the fire roared over the house. As it turned out, it was the house next door that was on fire. Fortunately, that house was vacant or not currently occupied. The chagrinned officer apologized to the lady for breaking her windows. The cop's supervisor asked why he broke so many of them and the officer responded with something along the lines of not being about to break open a large enough area to actually gain entry himself. While bothered, the old lady was smiling by the time it was over and the police had said they would certainly pay for the damage.
I can live with mistakes like these. To err on the side of being too safe is often just an inconvenience. Erring on the side of not being safe enough can result in trajedy.