system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Assume Revan is on the light side. Why didn't the Sith on Korriban sense his alignment?
gpt
A. They probably weren't expecting a powerful light-side user to just waltz into their home planet, so it's not something they look for. 
B. Hiding one's presence in the Force is an age-old technique. Seeing how Revan was someone who had spent a lot of time hiding recently (and in his past), this was probably a natural skill. He may have even been doing it without actively thinking about it. He clearly wasn't worried about it enough.