How to unparse HTML in ?
 

How to add a new field to fill by user in a safe way? How to unparse HTML in fields? (Note: not in user customfields that vbulletin provides by default) Do I need to use $bbcode_parser here? Any ideas?

Why don't you try it and see if it works? It's normally the script tags that are the dangerous ones. You can also use htmlentities if you can't find the html parser, but you won't be able to parse BB code with that.

Thanks for the answer. I've read a bit about it and I think now it's a better idea to clean user input before the data hits database if it is only letters or numbers. :)

You should use htmlentities with ENT_QUOTES