I've only done this once, at the end of a job interview out in the burbs. I had been dropped off by a friend, had almost no idea where I was, and had another interview lined up shortly after. I asked the security what the best way to get a cab was, and they offered to call one for me. I think it's perfectly within reason, although they may be more apt to do it if you set the situation such that they offer to do it.