That's a bit presumptuous, isn't? You don't know anything about the couple's circumstances, the nature of the trip, or the GF's financial temperament.

Depends on the day and time, and the luck of the draw, but a shuttle to the strip isn't necessarily a more aggravating option than a cab. There can be long lines for cabs, they get stuck in traffic just like shuttle buses, and you can easily get a cab driver who tries to rip you off by long-hauling you through the tunnel. Someone new to LV travel is especially vulnerable to the latter.