The widgets provide the response (from the player), so this would be a per-widget issue.
This is no longer an issue in Crossword (all non-alphanumeric characters are blocked automatically)
For the widgets where this is still an issue (example: word guess), it looks like they intentionally do this for security purposes. A better solution would probably be just to strip/block the < and > entirely, rather than replace them with < and then go back.
Tested in Crossword, notice the
<
characters: