First, except for turbines, there are no special REQUIREMENTS for flying fields or flight line equipment. There are RECOMMENDATIONS and SUGGESTIONS, some of which even make sense.

Second I was TOLD that the reason there is a fire extinguisher requirement for turbines dates back to the days of the propane engines where there were blow backs and fires. I can see why a fire extinguisher would be a good idea even with Jet A because the exhaust is hot enough to toast lots of unintended things that just happen to drift by the tail end.