As an Australian I can comment on this, theres this wonderful thing called "Context"
At McDonalds they refer to them as fries, but if you ask for a large chips, they know what you mean. If you go into a petrol station and ask where the crisps are, nobodies head explodes. If you go into a place that has ALL 3 (french fries, chips and crisps) and say "Can I get some chips" the person will ask for clarificaton.
British roots and American television has made OUR english quite flexible.