When people introduce themselves, they sometimes tend to give their full name and sometimes only the given name, without mentioning their last name. This depends on the situation and the people they were introducing themselves to.
Normally, to strangers that they just met and would almost likely not see again, people would only tell their given names, not their last names, unless it was some obnoxious young master who wants to flaunt their house name so that they can do whatever they want to without facing any consequences.
Since Erika had introduced herself using her full name, she expected him to do the same, but when he didn't, that surprised him.
"Maybe his last name was somethingweird", she thought as she moved on.
There are many names, including some house names, that are weird to spell. So, she didn't think much about that. In time, she would know his last name if it was meant to be. There was no need to think much regarding that.
