From an other suggestion:
Correct French, Scandinavian, German etc. spelling should be possible and allowed. Encouraged, in fact. The current system is discriminatory and tends to lead to confusion.
In my opinion not a good idea. All registers and databases are now working on the "simple" spelling of the vessel names: not using á, ä, ö, ú, etc.
In Europe are a lot of countries with special characters: Iceland, Norway, Sweden, Denmark, Poland, Hungary, Portugal to mention a few.
Characters like æ, þ, ø, å, ű, ñ, ß, ê are not on our keyboards: do you know how to make them? Many also different in upper and lower case. Introducing them will be additional work for the admin team because the posters simply will not bother about it as to difficult, as there are now also posters that never bother about the correct category.