Every single time I watch a cooking show where shrimp is being prepared, there's always an instructional point on de-veining it and sometimes an explanation of what the 'vein,' actually is, but I never see the same for lobster.
Lobsters have a much larger 'poop shute,' and are even easier to de-vein than shrimp but it's always ignored.
There's a flap that goes over the tail that is easy to pull away (a piece of meat I love and seperate mostly for that reason) which exposes the... 'butt-crack,' looking crevice of the tail with the great big poop-shute going all the way down the crack. Very easy to peel away intact.
I always de-vein mine and find it funny tv chefs are squeamish about shrimp 'veins,' but make no issue of chowing down on lobster poo.