I thought this strategy up and I have yet to execute it but I want to share it.
1. Don't witch until necessary
2. In a VFRy town, get a Vig to claim on the stand. Anti scumread them enough so you know they are town and not mafioso.
3. CC Vigilante and get them innoed for a shoot-off
4. Witch them into themselves
5. Say you shot them, don't die of guilt, and say they were disguiser
At this point if mafia is smart they'll realize you can't be vigilante and might correctly conclude you're witch. If you're convincing enough you might get town to disbelieve that say there wasn't disg.
Normally I just get to step 4 and witch them into jailor or something, but if you're not a day or two away from majority and there isn't a medium, this could prove interesting.