system
Given the following post, respond as if you're commenting on Reddit:
human
Does stealing increase social welfare?

If a thief values my cell phone at $300 and I only value my cell phone at $200, does his stealing my cell phone when I am not watching increase social welfare if nothing else in the economy changes?
gpt
Yes, but only because you've laid out the maths so simply. If you gave goods only to the people who valued them the most you would maximise social welfare. 
Having said that, the topic of loss aversion (behavioural economics) says that losses are felt more strongly than gains. In terms of this example, your gain in utility from you receiving a free phone will be less than your loss in utility from having your phone stolen, so it's unlikely that phone theft will be social welfare increasing.