[nickonline]

If it's anything like where I live it's not necessarily monitored or enforced. If you accidentally tell the cabbie where you want to go before getting in they'll just drive off.

If you're already in the cab when you tell them then they're not likely to tell you to get out.

[rickyc091]

Yep, a lot of times the driver will ask you where you are going before letting you jump in.