And what does this solve? A user mistakenly entering an extra plus sign gets a validation error. While user mistakenly entering an extra alphanumeric character

And what does this solve? A user mistakenly entering an extra plus sign gets a validation error. While user mistakenly entering an extra alphanumeric character (far more common) does not. Maybe they could ban adresses with `q` as well. Most people's names don't contain Q, so might be a user error.