People should be compensated for the hours they work. At least if the business is running their ship above board. So, while a customer may come in to the establishment 1 minute before closing time, as far as the States are concerned, that employee continues to get paid while they serve. The issue really comes in where the employee may not want to stay and that is the discussion between the employer and employee.
I have been salaried and hourly, I have freelanced, and I have worked for free as a volunteer. But I am currently hourly, and I know that once I exceed my schedule hours, I qualify for overtime. When I used to waitress/bartend and made sub-minimum wage, I lived for my tips. I never really had a problem with someone coming in late, because I knew that was another opportunity for me to fatten my wallet.
Though, let it be stated I don't have kids (chose not to go that route) so I didn't have a family to rush home to or take care of.
I don't understand this concept of serving a customer and not getting paid... is that something that happens a lot in Australia or the UK?
Maybe it happens in the US and I just have been lucky enough not to experience it, but there are labor laws to protect employees from such abuses.
What I also think stems from this issue is that many people no longer enjoy working. There is a sense of entitlement, rather than appreciation, that comes with a job... and I think it is important for people to be reminded that having a job is a fortunate occurrence... just ask anyone without a job. Looking for work is the toughest job of all.