Savage said:Of course "hiding" Luke away from Vader by giving him to Vader's step-brother and keeping the "Skywalker" name wasn't too smart in the beginning, but what're you going to do? :)
Hide in plain sight.
Vader (thinking): "Obi-Wan brought a kid named Skywalker to live with a guy I found out later was my step-brother on the very same planet I grew up on? That's too much of a coincidence...gotta be a bullshit rumor."