Well, I can see Andrew's point (this isn't something to put too much energy into) - but I can also see your point (the values simply shouldn't be that high). I usually don't bother with validation myself, but the one run I did on the CX gave delta E's of 0.24 max, 0.06 average and 0.03 white.
The actual calibration and profiling processes don't display all that many patches. So the validation puts up a whole lot of patches not previously measured, and then compares measured against predicted. As such, I think it qualifies as a valid procedure for checking the accuracy of the whole process and the numbers do have a real meaning.
If there are any real inaccuracies here, they're likely to be in the sensor rather than the panel itself. The Spyders do have a bad reputation, but my impression is that the Eizo-branded units are delivered to tighter specifications. I have compared a stock Spyder3 against an Eizo EX-1, in ColorNavigator, and then compared both against an i1 Display 3. The EX-1 and the i1D3 were for all practical purposes identical, while the stock Spyder3 gave different results which were clearly off.
That said, black rendering is not the strong side of IPS panels. Unless specific measures are taken, the characteristic off-angle "IPS white glow" can be very pronounced. The Spyder sensor, with its shallow construction, may be vulnerable to this. The i1D3 has a lens construction giving a longer, more directional light path, so it should be more immune.
I had an NEC P232 that had this white glow to such a degree that I always wondered whether it would affect black point reading, even with an i1D3. Great monitor otherwise, but blacks weren't really reliable. The Eizos I have now both have some sort of polarizing film so that black remains black from all angles.