I frequently require water from cafe's to heat DD2s bottles - I tend to use my own little bucket or sometimes just a large takeaway coffee cup and put the bottle in there. But I ALWAYS buy something, and am very appreciative and grateful as I understand it takes the staff members' time and the cups cost money etc.
If the cafe asked me to pay for the cup I totally would but this has never happened.
When I fed DD1 formula I used to carry around cold water in the bottle and if need be, I would ask for a cup of boiling waater and mix my own bottles. Again, I was never charged for the cup but I ALWAYS bought something.
I didn't see the article, but from what you guys have said, I agree with the cafe. It's a bit like someone wanting cash out on EFTPOS and not buying something (well sort of - hungry baby and all is a bit different but you get what I mean) .