But safety is not the only concern. If there are some out there that believe that a propensity to steal will not necessarily end in a big silver cylinder plummeting to earth, there are other considerations.
What this behaviour displays is a blatant disregard for the rules within society. Wouldn't you think the airlines would be concerned that this would transport into an even more blatant disregard for rules and/or procedures the breach of which would not necessarily end in a prison term.
Again putting aside the safety considerations, there are multitudes of policies that are designed to enhance productivity and efficiency that this chap may well consider surplus to requirements.
Which is basically exactly what Gaunty just said.