Have some way to filter out invalid XML characters when importing (or better yet, avoid them from being entered in the first place)

Problem Definition

Currently, there are times where an invalid XML character that is inserted into the instance can cause problems when trying to import the XML export of that instance. This can lead to frustrations (as they would either have to find it manually, or run the XML through the XML cleaner.

Suggested Solution

It would more effective (and efficient) if the import can automatically filter out these invalid characters. A better (but possibly tougher alternative) would be to disallow those characters from being inserted into the instance in the first place.