Posting tubes of paint

Just bought some supplies from Ken Bromley - excellent service plus they'll post things Royal Mail, a bonus if you live on Skye! However, they won't send tubes of oil paint by Royal Mail - apparently they're classified as "solvent based". Surely this cannot be correct! I contacted their sales dept, saying: ".....tubes of artists' oil paints are not solvent based. The oil used (linseed, safflower etc) is a drying oil, not a solvent. The pigment is suspended in the drying oil, not dissolved by it. Crucially, the paint does not dry by the evaporation of a solvent - the drying oil polymerises by interaction with the atmosphere. Solvents (turpentine etc) can of course be added - but this is done by the artist as part of the painting process, in order to modify the characteristics of the tube colour. Indeed, it would be more accurate to call watercolour paints solvent-based, as the pigment is both suspended in a binder (e.g. gum arabic, which serves much the same purpose as the drying oil) but also water - and the paint dries by evaporation." To my surprise, and their credit, I got a quick reply, which said: "There is a European appeal from multiple art material manufacturers as regards to the matter of Oil paints being solvent free and what constitutes an artist paint. This is likely to go on for some time and all art materials suppliers are keeping their eyes on this appeal as it affects all of us." This is the first I've heard of this. It seems ludicrous to me - what dangerous solvent is supposed to be present in tubes of oil paint?? Has anybody else any thoughts about, or experience of, this?