I actually have found those "blisters" on a few cotttontails (haven't found one yet on a jack rabbit), and I've only found them on cottontails that I've shot at my relative's property. I've never found those blisters on rabbits I've shot at my public land hunting spots... at least not yet. There are allot of coyotes and pet dogs in the area where my relatives live, so now that I've read that article, it makes sense.
Like the article described, there are usually white spots on the liver when you find the "blister" somewhere on the body. Of the three rabbits I've shot that had these blisters (Cysticercosis) one blister was on the neck area and the other two were on the hind of the back leg, underneath the membrane of the leg muscle.
In fact, one of the rabbits I shot this last weekend had the white spots on the liver and the blister on the back leg. Not knowing what is was or what was causing it, I have been throwing those rabbits out and only keeping the hides to tan. I didn't want to take any chances that I might contract something from it or get some sort of infection. It sound like as long as you carefully remove the blister and cook the meat thoroughly that you should be alright though. Still, I don't know that I would eat a rabbit that had that and will probably still throw those out just to be on the safe side. After seeing those blisters first hand I have to say that they do look rather digusting.
One thing I always do before putting the rabbit meat in a bag especially if there is more than one rabbit being put in the same freezer bag, is to cut the rabbit open and examine the liver and other organs. If I'm gutting them in the field I examine the "guts" and organs as I'm field dressing them to make sure the rabbit is worth keeping for consumption. If not, it goes into a separate bag in my backpack and then I toss it out after getting back to home or camp.
There are all sorts of things to learn.

I learn something new every day.