I certainly wouldn't be seen up there without crampons, but I suspect he knows what he's doing.
On my first Tanners ascent years back, we caught up with a guy in sneakers. It was a bit challenging for him to say the truth, especially since we chose a variation which exits the coloir to the right (East) instead of following all the way to the saddle. The variation saves you the the need to descend to the N and reascend, but it is steep and stiff.
In any case, AH, if you haven't been on the West ridge of Dromedary, keep in mind that there is a cliffy section where it makes perfect sense to remove crampons, and few people put them back on again for this short ridgewalk above the cliff.
There's always a perfectly logical explaination, isn't there. I didn't even consider the possibility that he WAS wearing crampons, but isn't now. Silly me.