There is also the chance that the switchers (say a maid working in conjunction with others) may hear of the sudden hospitalization(s) in grave condition.I am trying to figure out if a person dies from one drink in a bottle, there is plenty of booze left. Plenty for someone else to drink it but they do not die.
The bottle will then be refilled with one drink gone? Refilled with good or bad booze? Bad booze but it does not kill the next person?
They then get worried and re sub the alcohol with either a cheap but safe generic substitute or even street alcohol made by somebody who knew what they were doing- at least somewhat.