I work on the basis of assuming that other people haven't done what they are supposed to have done, and about 1% of the time I'm right.
I would say finding snags on a walkround is probably higher than 1% - trouble is it very rarely is the Eng Cowlings.
So the walkround needs to "target" the frequently found problems (lights cracked, birdstrike, brake wear, tyres etc.) and the "high danger" points. Also, as engineers have been withdrawn / servicing less frequent, the walkround has altered from "second checking the engineer" (cowls) to an actual turnround - what has fallen off / got damaged / worn out? Bear in mid the cowl check is just one, not emphasised / highlighted line, in the checklist.
It's academic now for most A320 operators, especially BA - people will check cowls closely for a year or 2. But we must make sure we don't enhance that to the loss of something else (the brigade of lights, knee pads, mirrors miss the point the cowl is but one of many elements), and the "solution" outlasts the awareness period.
NoD