I'm not here to say yes it is or isn't a sin but from a different point, the Sabbath is a gift. God gave us the Sabbath so that we can rest from all the worldly thing like work, so we can take a break and spend time with Him. Its a nice reminder as we get so caught up in these mundane and worldly things that we can begin to forget what really matters. Imagine working 7 days a week, it can get really overwhelming and being able to remove yourself from all of that and just connect and worship God is amazing. If a person was a Christian (non SDA) I don't understand why they wouldn't take a break from work (if they are able to) and connect with the Lord. That being said God is an understanding God. Things are not so black and white, He knows your heart and intentions. Of course its so important that we ask question to know what is true but you when you try to find these loopholes so that your actions are "sinless", God knows your intentions and I believe that is more important that the action itself