This could by done by looking for warning templates that are in old text and missing in new text of a diff, it would be pretty unreliable though as diff internal parser is screen scraping html right now as there is no way to get the data from API directly but it probably could work.

Now what huggle can easily do if it recognized that:

• Raise the score of edit so the edit that removed warning would be higher in queue - of course this works only if user doesn't want to hide user talk edits and most of us probably do
• Somehow raise the score of user who did that?
• Increase the current warning level of user to that of removed template in case it was lower.

Challenges:

• Adjust the template parser to figure out if removed template wasn't expired
• Figure out if removal wasn't made by a trusted user and ignore that (talk page wiped by admin?)
• Flag somehow the user as "template removing user" so that we can add an extra template to their talk page if needed

Occasionally, you (as an anti-vandal patroller) may want to remove a warning if you placed it wrongly, so it should probably only catch users removing warnings from their own talk pages.