"What is the probability that a lavac owner will suffer a brain aneurism while desperately pumping away on the henderson hand crank while attempting to maintain a vacuum?"
Zero. There's virtually no effort required to pump a Lavac. You're not creating a vacuum, just a pressure differential sufficient to lift water a foot or so. If you're pumping hard enough to endanger your health, you should look to your diet, because you must be excreting granite turds.
Nothing wrong with the none descript Chinese import I bought for £80/£90 a couple of years ago as far as I can see.It still does the business /forums/images/graemlins/ooo.gif