Stellarium is a great product and fun to use, but I have seen it misused by some as well. For example, some have tried to use it to prove various points about stellar and planetary alignments with man-made structures (e.g. Stone Henge or the Pyramids at Giza) during different epochs. This is "bad astronomy" since Stellarium does take some algorithmic shortcuts in order to enhance its performance. For example, its precession calculation simply multiplies the average rate per year times the number of years from J2000, if I recall correctly. Good for a few decades +/- J2000 but unreliable for precision archaeo-astronomy.

-Veeger