"I suspect that if someone is working at a bench in the wet lab then you have to look at how many earbuds are being worn. One means "Yup, I'm listening". Two probably means "Do not disturb: I've already made a mistake setting up this PCR and if you talk I shall ignore you. If you persist, I shall stab you with my Gilson". Whether the hands are gloved or not might have some bearing on the situation."
Works the same way here. I don't have an iPOD but I appreciate not having to guess when someone's trying to drone me out.
Funny how iPOD lab customs have evolved in parallel in our lab on the opposite side of the world. Maybe it's a colonial thing .
PS - Watch out. Black Knight is apparently not his real name.
Have a look add your iPOD etiquette lessons to the mix...