Our SOPs are for the guy whose sector it is to do the walk round when two-crew and for one of the heavies to do it when there are extra bods available. This can be varied according to personal preference but most people do it this way.
Unless we’ve landed somewhere off-schedule, we always have engineering cover, so I use the walk round to concentrate on the stuff that’s most likely to cause trouble, e.g. is the gear pinned down? Tyres and brakes. Engines. Puddles of fluid underneath. Has someone made a dent/hole and not owned up to it? That kind of thing. Does it “look right” or are you getting a nagging feeling?
Most carriers run to a schedule which leaves only a certain amount of time for pre-fight preparation. You could spend a disproportionate amount of that peering into nooks and crannies and be none the wiser, then have to cut corners elsewhere. There has to be a balance. You’re not doing a D-check...
It does surprise me that there aren’t proximity sensors fitted to engine cowlings, considering the risk involved. Most of the other doors and hatches do have them but the consequences of going flying with them not quite right are often minimal.