Shouldn't the law deal with abusive drunks?

Norman Lamb, Lib Dem Shadow Health Secretary, has today published a spokesperson's paper. This is not a policy paper, but rather Norman's personal contribution to the party's health policy working group.
I was interested to read the quote from Norman in the BBC reporting of this launch:

"If you go out on a Friday or a Saturday night and get very drunk and you end up in accident and emergency, and you are foul and abusive to staff who are already overstretched, then is it right that you should get that care entirely for free, or are there consequences to your actions? "And I think there is a case for saying that someone in those circumstances should be asked to pay for their care."

Now I am sure this is not all that Norman said, but this quote and similar ones have appeared all over the media. I have no problem with a debate about whether people should be charged for self inflicted health problems - be they drink or drug related injuries or the health impacts of drink, drugs and cigarettes.
But the "foul and abusive to staff" line worries me. Does this mean we set a precedent for spot charging drunk people for services? If so, why stop at health services, what about bus drivers - should they be able to double the fare for a drunk getting on the bus and swearing?
Yes there is a clear problem with drunk and abusive people, especially in hospital A&E departments. But surely the way to deal with drunk and abusive people is to use the law. I just don't see the connection between the need to clamp down on anti-social behaviour and funding models for the NHS.