In the UK, there is plenty of computer systems that refuse to acknowledge that people or places can have non-ascii chars in their name, and ask you to correct them.. or even refuse to work possibly because they are comparing broken different encodings of them. Even paying tax by debit card seems to be impossible with their chosen payment processor if the name on your card or parts of your address does not match the constraints of the english alphabet.
Avoding any international characters, both when registering addresses and when inputting them in forms ends up being the path towards hopefully being able to spend money with credit/debit cards though. For various other non financial forms fuzzing the systems with what should be common enough european text and laughing as it fails is safer fun though.
