Banned technique (kinjite): immediate loss + potential commission discipline; Mawashi failure (belt comes off during match): immediate loss (rare, considered dishonorable); Premature start (henka jump): tactical move (not technically illegal) but heavily frowned upon at Yokozuna rank
Why people argue about this
People often assume that a banned technique (kinjite) in Sumo only disqualifies you if you're caught by your opponent, but actually, it can be called by an official at any point during the match, even before your opponent touches you, leading to confusion about when exactly this penalty applies.