Sure but how often does it happen? Poker is a game of probability and incomplete information, so if I have 30 hands on someone and the stats tell me he is tight passive, yes there is a small chance that he cought nothing for 30 hands. But it is much more likely he really is tight passive, so I like my chances.
If you dont have the HUD stats (for whatever reason) and get only normal reads on a table, would you ignore your reads for the first 100 hands?

And with loose players it's even more likely that the stats are correct, if someone has 60% vpip over 30 hands, he is loose...I cant ignore the stats just because there is a very small chance he cought premium hands for 30 hands.

Also, I usually check the stats again after a larger number of hands, just to see how they change and sure, there are small changes. Someone might go from tight-passive to tight-neutral over a bigger hand sample, but I cant remember the stats changing from passive to loose or the other way around for example, just because the sample went from 30 to 300 hands.