The acronym BASE stands for the places from which jumpers usually leap: buildings, antennae, spans and earth. It's considered even more riskier than skydiving because of the shortened time between jumping and landing.
So, I thought I'd bring this to your attention, because I am dead certain that many readers of my blog, like me, get the skin crawlies upon reading something like this, especially from "professionals." And I get a kick out of sharing that icky-grammar feeling! Consider it an early Halloween present!