I don't understand the downvote, because I can easily think of non-altruistic reasons for this move.
1) I have no doubt Google already tracks their contractors' staff turnover. Every industry has institutional knowledge, and if staff turnover is high, not enough of the knowledge gets transferred. If the prestige of being a Googler is enough to counter that trend, it may be well worth a lot more than the monetary cost.
2) Assuming the detail about "gbus" access is true, the security guards traveling on the buses will have personal incentives for keeping them safer.
3) This move may attract the kinds of people Google wants for their physical security. (Related to point #1.)
So while Google may well be riding the social awareness wave for PR purposes, there are bound to be real corporate reasons behind the move too.
1) I have no doubt Google already tracks their contractors' staff turnover. Every industry has institutional knowledge, and if staff turnover is high, not enough of the knowledge gets transferred. If the prestige of being a Googler is enough to counter that trend, it may be well worth a lot more than the monetary cost.
2) Assuming the detail about "gbus" access is true, the security guards traveling on the buses will have personal incentives for keeping them safer.
3) This move may attract the kinds of people Google wants for their physical security. (Related to point #1.)
So while Google may well be riding the social awareness wave for PR purposes, there are bound to be real corporate reasons behind the move too.