Why add oil in the slash gap?

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I was watching this video, just passing some time: http://www.youtube.com/watch?v=wJRpBCVfN_Q

At around 6:58 she oils the slash, does anyone know why?

is that it is going to be a while before it sees the oven heat and she is afraid it will close up before then and not bloom as she wants?

.... from my youth (maybe 35-40 years ago?) for commercial "memory foam" white bread, where the gimmick shown on the ad was butter being poured into the slash of the panned loaf before baking.  The voice-over announcer alleged it added buttery taste to the bread, but I can't say one way or another how much of a difference this would have made.  Neat visual gimmick, though.

was taught to slash and oil that way by a master baker somewhere and it seems to work really good for her - so no worries.   Looks way better than my single slashing and non oiling  :-)