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For stuff like getting caught shilling or other such breaches of decorum?

The "jail" could be confining the naughty user to a certain section of the site.
Example:
"@sampleuser you have been convicted by a poll of your fellow goats and are sentenced to 7 days of confinement to /soapboxbanhammer... Matty good have mercy on your soul"

Then limit that users' posting/commenting/viewing to that one sub.