Definately agree with dont reward bad behaviour!
My last flight back I had a pax sitting in WT+ Asking for something which was not availible in this cabin. I politely said no and offered an alternative. Her Husband then decided to have a go at me suggesting I "March up to club" and get it to which i refused. He then had the cheek to say "I" had the attitude problem to which i reminded him that at no point had i been rude but simply tried to explain that we are not allowed to contaminate the product ( i just love the phrase). He then said he would get it off the CSD instead!!!! So I then made a point of advising the crew what had occured and to be sure none of the crew would allow him to get what he wanted. My Purser also said she would speak with him, but the big mistake he made was telling another colleague of mine on the flight that I was a "P*&$K" so my purser was able to hold that against him if she needed it.
But the funny thing is....I was actually going to get the item for them anyways until they started to act like that!!!! It was only over a packet of walkers!!!!