Certainly, the easiest way to do marine policing is at the launch ramp before the boat gets wet—“blow here”—or to catch them when they are coming back.
In Ontario, the Liquor Licence Act says that you can only have alcohol on board to be consumed if it's a residence, which requires permanent sleeping accommodation, galley, and head facilities—toilets—and you have to be at anchor, aground, or tied to a dock. It's very restrictive.
I was chatting with Mr. Blair earlier. I do a lot of accident reconstruction in my line of work, and the number of accidents where people have gone out for a day of drinking and using, typically marijuana..... Going boating and drugs and booze seem to be very popular. We in fact worked on one case with John doing the reconstruction and me writing the report for one of the sides in a civil suit.
This has been a problem for a long time, and it's one that the police struggle with. However, as John said, they are equipping themselves better and taking this into more of an account.