Well the issue discussed in the article reffered to below is one that is at this point very contentious to say the least. But it seems from the results of this study (and some "unoffical" studies done over the last few years)is that it MIGHT be helpful to provide a small area of the enclosure which has a high humidity for hatchling sulcatas.
I don't think ANYONE would agree that making a whole enclosure wet or even fairly humid is a good idea for desert/grassland torts like sulcatas.
BUT if your enclosure is large and MOSTLY DRY, the torties might benfit from having a hide box which has a high humidity.
But we really should be careful about jumping to conclusions from the results of this study as many more like it need to be done. And we should NOT be misinterpreting the results to say that "sulcatas need high humidity" This is surely not the case based on field studies . Further, the risk of humidity combined with cool air are great.
With that said it should be noted that many people keep sulcatas in warm humid places (florida, brazil for example) with no apparent problems.
However it still seems that the best advice is too keep them warm and dry, offer a warm basking site and possibly allow for a high humidity hide which does not cause the rest of the enclosure to become overly moist.
Many keepers of forest species like red foots and american box turtles have found that having a humidity gradient (so that one region is more wet than another), analagous to the thermal gradient that we all use for reptiles so that one area is warmer than another, is helpful in raising hathclings. It seems likely that something similar may eventually be widely recommended for tortoises from more arid climates but as I am not a tortoise person (and far from expert) i will refrain from advising it.