Yeah but a meter can show a locked rotor too.

Wait, is the goal here to make pie or start a cleaning supply company? A full cup of vinegar sounds like you're trying to pickle the flour. I've heard of a spoonful to stop gluten from forming, but that much acid would just make a weird, tough mess. Some of these "secret tricks" are just people mixing up their measurements.

YouTube makes us all weekend handymen now.

Ever try to fix something with that cheap glue and have it fail at the worst time? @paulw53 is totally right. I had a garden chair leg snap, used a bargain tube, and it held for a week. Then my cousin sat down and it just gave up, left a dusty mess. Felt so dumb because I had to redo the whole fix with the good stuff anyway. That false saving cost me an afternoon.

Appeal it right away and ask for the exact phrase they flagged. Sometimes the mods just see a hot button word and auto ban without reading the full context. Your friend needs to get the specific rule violation in writing to fight it.