To clarify, "boiled" linseed oil is a misnomer.  Years ago, they would boil linseed oil to get it to set up more quickly, but that process also made it tend to set up in the container.  So now they don't boil the oils to start the polymerization, that add a metal drier.  The most common ones were lead driers, now we are likely to see a variety of other metal compounds used to initiate the exothermic setting reaction.

But heating the oils also will work.  And in this case you can worry about all natural oils.  There has been a bunch of spontaneous fires in piles of laundry still warm from the drier that have been attributed to olive oil and some essential oils used in massage that didn't completely wash out of the sheets and robes.

I'm sure it's pathological, but something about that story makes me very happy.