If the lore is not outdated, I believe hurting/killing pet yukkuri that belong to other humans is the one and only kind of abuse that even professional abyusers look down upon. Not sure the "dying painfully = awful smell" thing tracks though, if it was canon (or even just limited to Takumi's works) then almost every single city in his verse would have a constant smell of poo-poo that would warn all nearby yukkuri of human presence. Hell, yus die brutally all the time even with NO humans involved, so this phenomenon would be immediately recognized even by the stupidest clans and families.
Even though Marisa does nothingIt is common that pet yukkuris die from smelling it.Let's be sufficiently cautious when using it.However, because the stink can penetrate the wall,This stink is widely used as a yukkuri repellant.When a yukkuri died painfully,the corpse and paste let out a tremendous stink.Marisa is dyingReimu is leaving easy!Can't take it easy at all!Stinks worse than poo-poo!