Why do they do this? One reason at least is because they are being told, in videos and blog posts, that frankincense oil contains boswellic acid - the antitumoral active ingredient in frankincense gum resin. But it doesn't, and the simple reason is that boswellic acid is much too heavy a molecule to be volatile. The are are several boswellic acids found in frankincense gum resin, and they have molecular weights in the 450 - 500 range. However, volatile molecules - those capable of evaporation - all have molecular weights below 300.
As you can see now, there have been a misinformation about this and it needs to be clarified. I would LOVE to tell you that frankincense essential oil (or any other EO) can cure cancer... but it doesn´t.
If you need more information about this, please follow the link below and you can read a complete explanation from the expert.
REFERENCES
Frankincense Oil And Cancer in Perspective, Robert Tisserand: http://tisserandinstitute.org/frankincense-oil-and-cancer-in-perspective/