It's not as immoral/illegal as the people who go to the bars order a big round wait till it's all been placed on the bar and then say oh by the way can I have a jd and coke or something then as soon as the servers back is turned they leg it with the drinks.
I have been known to hop the bar and chase them down if I'm having a really bad day!
Some places here have rules (on a notice) about serving which I guess are to stop people doing that - didn't know the reason why though.