One of the things about drinking in the habour, the captain/pilot should NEVER drink..EVER. That's a recipe for disaster. In addition, if you get caught it goes on your car licence as well.
As for passengers, have them put all their drinks in a plastic cup kind of like a tupperware, don't have them flaunting it, and keep the music to a reasonable level.
The only time I ever got hassled was when I was anchored for lunch at humber bay park. Some asshole cop on a jetski came buzzing around and made us take all the beer out of the cooler under the transom seat and put it in the fridge downstairs, and take all the food out of the fridge and put it in the cooler. He actually stood there and watched.
So fine, we fire up the BBQ and start prepping to make lunch and the shit head is puttering around and around and around the boat. (2 cycle stinking up the place). I called over to him: would you mind? You're stinking up the place and that motor is REALLY irritating. He just stared at me.
SO I had my passengers shut off the bbq, pack up the lunch stuff, I fired up the engine and hoisted the anchor. Buddy turned to follow us. So I'm outside the little harbour and sure enough, asshole is right behind me, not 20 feet. He follows for like 15 minutes like that (I'm only doing maybe 5 mph).
So I said "fuck this, everyone hang on" I opened her up. Now when it was new, and had a freshly waxed bottom, I could hit 60 mph on the speedo (prolly 50 actual). Well, buddy tried to catch up but nope....we got about a mile away and found a small floatilla of power boats, mixed in with them, went out the other side and doubled back to the Toronto harbour.
BTW: it IS legal to have open liquor or beer on a boat as long as your anchored and the anchor is actually hooked......