Why do webforms often refuse non-ASCII characters?

[Jens Maurer]

On 29/01/2025 16.39, Bríd-Áine Parnell via Unicode wrote:
> I'm hoping someone can help me out with some information. I'm doing some research into the refusal of accents in names (and other multicultural naming conventions) in online webforms. For example, in Ireland, there was a campaign recently to get the government to mandate acceptance of the fada in Irish language names (Seán instead of Sean). The campaign was successful, and the law changed in 2022, but it's only a requirement for public bodies, companies do not have to comply.
>
> During the campaign, reports were made to the Data Protection Commissioner on the right to rectify about some of the companies, including Bank of Ireland and Aer Lingus. They defended themselves by saying that their systems couldn't accept fadas in names.
>
> I'm assuming that its systems on the back end, such as database systems, that can't accept the so-called special characters. My question is, why would this be, given that Unicode would seem to solve this, and modern databases can use Unicode? Does anyone understand what the value is in continuing to retain legacy systems that only accept ASCII or some ISO variants? Or is there a different problem happening?

The value is that it costs non-trivial money to replace those
backend systems, for zero commercial benefit.

For the airline industry, names seem to be all-caps ASCII, and
I wouldn't be surprised if there are some IATA or ICAO rules that
require exactly that.  After all, boarding passes need to be checked
against your name by a variety of people (ground staff, border
control etc.) in different countries, and trying to match
a name written in e.g. Chinese letters against a passport with
Chinese letters is probably a hardship for people not used to
reading Chinese.

Similar for international banking.

I note that those two industries were among the first to
embrace IT-based systems, and probably have the most legacy
to deal with.

Jens