Depends on how much overshoot you're willing to tolerate (which also makes it look like it's ghosting). The cheap things citing stupid low response times seem willing to tolerate quite a bit. I know at least TN type LCDs are usually not driven "all the way" even for full white/black. Going past a chosen "pixel off" (i.e. "white") point results in it taking too long to turn back up, and going past the chosen "full on" (i.e. "black") point can result in long-term damage to the panel, even though the panel does get darker. Some designs may exceed those points transiently, though, since, as you point out, you'll tend to overshoot a bit when you transition.
The point, though, is that they generally cook the test cases to give them the lowest number possible for a given testing criteria, since they know it's a number that the product is "sold" by.
The same thing happens (in the US, at least) with digital cameras and the "megapixels rating" (yes, I've heard sales reps say that) and is why you end up with 10MP cell phones and $50 point and shoots that don't have the optics to resolve anything close to that and sensors only a few mm across meaning you mostly just get noise at that res. But by golly it puts out overcompressed JPEGs with 10 million pixels!
What can be really misleading is that the monitors that naturally have lower response time (TN and VA panel types) require or at least benefit highly from non-causal overdrive waveform calculations so they have to delay the display slightly (a frame or two) in order to "see into the future" for those calculations. You end up with a "super fast" display in terms of response time but it's so lagged as to be useless for gaming, anyway. Gah...this is why I have my FW900s for gaming.