In reading games, a student may mark an answer just as the reader says time is up.
Example
During Presidents, a player circles an answer just as the reader says "pens down" or "exchange papers" or "time's up," etc.
Some cases are easy to handle. If a player marked an answer after the reader started calling out the correct response, the player's answer is invalid and the question/example scored accordingly. The player should be warned not to do so again. Another attempt to mark an answer too late can result in a -1 penalty and possible expulsion from the tournament.
To be continued ...