Congratulations, you are a TiddlyWiki hacker!

Hilariously, all it really takes is a single ], because this causes the filter syntax to become invalid, which causes the tiddler Filter error: Missing [ in filter expression to appear in the output and the conditional expression to become true. You could use any number of variations on the theme of making the filter syntax invalid.

A more complete version, riffing on the example we saw above, would be x]][x – that is, create an unconditional filter run for the tiddler [[x]] so there's some output to the filter, then open a new run which tries to match the text x against the password (presumably this will fail, but that will be OK because we've already added a tiddler to the final output of the filter run).