There are so many things that are involved in rust that the experts sometimes
have trouble predicting. If I (not an expert) was going to guess, you got some
salt/dried sweat from you shirt on the surface when you wiped it. The surface
had been disturbed, so any protective film of stable oxide or oils or whatever
was gone, and the moisture and whatever little bit of stuff from your shirt
promoted the rust flash. The particular alloy and condition (heat treatment
history, mechanical history, surface cracking, etc) also play a big part. It is
weird and not simple. I have done grinding of steels in the nastiest conditions,
wet, varying temperature, dust and grime, and the prepped surface stays pretty
good for days or weeks (think the aforementioned commercial ships or sewer
plants). On the other hand, the more common case is that when cleaning down
material under 'good' conditions, an hour later, there is a rust fingerprint,
suitable for enshrinement in a folder in Washington as a study in orange and
shiny, in the middle of the prepped surface where it got touched, followed a few
hours later by a full flash of orange, powdery rust. If the sum total of the
conditions favour a protective film forming, that's what you get.

That said, in my muggy workspace at home, I run the dehumidifier to keep
humidity 45% (this time of year it sits at 70% or higher without help)  or so
and everything gets paste wax or light machine oil. I tend to use sewing machine
oil for most things, as he price is right and it is a good quality acid
free/detergent free oil. I also use vapor corrosion inhibitor packs in the
chests, and tools that have their own cases get VCI chips. The the extent
possible, no water in the shop, either. If I bring in a cold drink, it sits on a
rag to soak up the sweat so I don't need to worry about setting something on a
wet ring later. Since I started getting really OCD about it a few years ago, my
problems with rust mostly went away.

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