Oh No! its the do list!
Most intake fires are due to the time between priming and starting the engine, this time gap gives the fuel that the primers put into the inlet system just upstream of the inlet valves to run down into the air intake and pool in the lowest part of the system.
The root of the problem is in the way most instructors teach the use of the check list.
Most of the students that I seen use the check list as a "do list".
It should take about ten seconds between priming the engine and turning the starter and another twenty seconds to check the oil pressure is increasing, the starter relay light is out (if fitted) and the engine is stable at 1200 RPM.
Only when this has been done and you have checked that the aircraft is not moving should the check list come out to check that all the required items have been done.
All the engine start actions from priming untill the engine is is at a stable idle speed should be "memory items" (or recall items in Boeing speak) this cuts down the chances of an intake fire to almost nill.
If you use the check list as a do list you are setting yourself up for an intake fire each time you start the engine.
The rest is down to luck most of the time the engine will start without a problem but if you have a backfire you will have an intake fire and if you are very unlucky you will destroy the aircraft.