Here is what Sony says about A99 weather sealing

The key word used is resistant. Even canon and nikon only say resistant. For warranty purposes is my guess. The only claims I have seen for full weather sealing come from Pentax and Olympus. Meaning if the elements cause damage to the camera they would have a hard time not covering the damages. Sony and the big two can get away with not covering the damages because the word resistant is not a guarantee. That's just my opinion.