A friend of mine checked in on Singapore Airlines a bag which had a box of matches in it. They are regular matches and not the "strike against anything" type.
My friend subsequently realised that these were banned on that airline, and went back to the baggage check-in location. The baggage check-in staff said that it was not worth the bother to retrieve them, and that security personnel later on would remove the matches if they thought they were a problem.
Presumably there is some chance the personnel later on would miss the matches, but the staff did not seem to bothered by this, which suggested to me that maybe there was no genuine safety problem here.
What's the rationale for this rule existing? Of course in life on the ground matches do not generally spontaneously ignite, but I wondered if maybe different conditions in the cargo hold made matches more likely to ignite on their own?