If you are working in a house alone and the owners fourteen year old daughter comes home alone, leave promptly.
Is that good policy to protect yourself against any lies?
I kinda get the point that you are making but would you walk away from the bus stop if there was only one other person waiting for a bus, ie a young girl, for the same reason?
That said, if a 14 year old starts making overtures towards you, then sure, runaway as fast as you can. How did you explain your absence to the client?