The "Blob" is remarkably similar to a method we use for winter carp, called the "Zig Rig". This involves casting out a very bright, fluro boillie or even a piece of yellow, white or orange rig foam, on a long leader so it susspends up off the bottom. Normally we try and get the bait to sit in the top third of the water.
Along comes mister Carp, sees this bright thing sitting at eye level and sees it as a very easy target.
Could the same be said about Mr. Trout? I am sure that its seen as "possible" food, and so the fish takes it, not necessarily to eat, but to just see what it is. We all know fish are curious wee beasties so the most natural thing for them to do is mouth something they think "might" be edible...and if it is, down it goes, if its not, its spat back out. I think the method works well in winter as there is not a lot of natural food about, so anything that looks interesting is taken, and whats more interesting in something big, bright and glowing sitting infront of your face?
Just a thought like!