Complacency or laziness. Either way, checklists exist for a reason and good pilots do them every f*cking time. Even if it's their 10,000th flight they go through the checklist.
Well this is a bullshit story. The 23 year old screwed up the landing and started to act totally bizarre after apologizing incessantly for damaging the gear intentionally jumped to his death
The canopy lock pin should be on the pre flight checklist. If it's not on, it should be on it. It may have been forgotten? The pilot is very lucky, lady. Make a mistake in the air whilst flying can be very unforgiving.
This happened to me on my 7th lesson. My instructor thought I was mad when I climbed out the seat and started to spin the propellor by hand to keep us going. It actually did nothing to help, he's not my flying instructor anymore.