There's definitely a fine art to RSA. Cutting someone off without warning, telling someone they've "had too much" or worst of all telling someone they're drunk or intoxicated are 3 certain ways to get them offside. If you're at the stage where you have to do the above then you've failed in the S of the RSA. RSA may be a law but it's also a duty of care. Alot of the pax I serve want to have 2 drinks fairly quickly so they can settle down and sleep. You can spot instantly the ones on a mission. Communicate with the other crew, pour floaters, drop off water to them and pace their drinks. Avoid getting to the stage where you have to tell them they can't have more drinks bc you've failed in the alcohol service. They're a captive audience and unless they're drinking their own booze then it should be a controllable situation. ( add sleeping tablets, pre departure drinks, altitude and emotions and it's gets a little more complicated )