The problem with domestic cleaning is that pre-existing defects and faults are totally, totally endless. This means that -literally- the cleaning staff could spend more time detecting and reporting faults than they would spend cleaning. It is a very fine line...for instance i once pointed out to a lady that her laminate flooring in the hall. was coming apart. This was my first visit. What i didnt tell her about were all the minor dings and scratches that i found all over the house.
No matter what happens, you will always get someone who blames the cleaners for any or all the damage inflicted on their home. The worry comes when those same people then start asking the cleaning company to take responsibility for it. This is why insurance is useful. You take the complaint to the insurance company, they then deal with your client. If YOU have the b@lls to take your own personal opinion out of the situation (and it strikes me that a lot of folk haven't and don't see the bigger picture) and let the insurance company deal with it, then you won't get quite so stressed. To me the problems start when people try to fight fire with fire and try to argue the point rather than seek expert advice to 'prove' what may or may not have happened.
You can write procedues till the cows come home, what is key to this game is correct training and spot-checks to make sure it is being executed. So you have instructions on cleaning laminate floor for example, but how do you PROVE that the instructions were followed in the event of someone saying that the floor has been over wetted?
My advice is keep an open mind about a clinet 'trying it on', take it on the chin, try not to worry about it, and if the worst happens use all the expert help avaliable to you. These things happen and in the main part you'll be making £££ as a result of working in folk's houses. Occasionally you'll be asked to pay some back. Its the name of the game.