Interesting. Got anymore to share, or should I just keep asking?
I'm not surprised that the oil would absorb the dye: it will absorb food coloring just as well, and if I remember correctly, can actually suck it straight out of water too!
So the question becomes: where did the oil come from?
An immediate source is our very own fingers. I can also easily imagine that a number of our components might have been sprayed, possibly for shipping purposes, to keep the product "shiny" when it arrives.
Good tip on the DTek dye: I guess we'll have to avoid it all together, no matter what.
I suppose that some kind of cleaning process might be in order. Maybe not something as drastic as what Airspirit did, but it would definitaly require some kind of surfactant, to extract the oil out of the loop...
I wish I had the time: I haven't even tested the Rit whitener, to see if it foams up!
Did you consider using a UV reactive highlighter pen, as a source for the dye?