one of the staff of an esate agent we work with is known to use as the "can you just guy", it's an ongoing joke we make a bet to see how many can you just he asks when we see him. me favourite was when he had asked for about 5 in the property, simple things like clean banner at front door, then window seal outside, then lampshade in back garden etc, then once he'd left he was still calling to give more can you just's.
it's a tuff one to chose what to do as you don't want the person going else where but you want respect for your work. imo carpet cleaning appears (i'm yet to actually do it myself) like a very well paid job for doing little so can easily afford the extra time for can oyu just jobs. of course doing an extra room is a loss of say £20, but then it's not cost £10 in supplies so not so bad. the guy we sub carpet cleans to often does extra little bits like a small study and customers respond well.