Re: Accents in username
It has to do with people using different character encoding for their database tables other than UTF-8. I’m probably overstating the threat as the same problem exists on all data input and we filter it out the problem there. I was also just reviewing WordPress injection attacks of days gone by, so it was on my mind.
In any case, the solution in the future is to change your display name after registration. Display names are UTF-8 friendly.