I'm afraid I don't quite get it. I don't live in Cabarete year round, but I have been going there for 2-3 months the last 7 years. I go out to the bars at night, admittedly consuming several more beers than I actually "need", cruise around on my rented moto all around the North Coast (never after I have been drinking, and never after dark...the roads are dangerous enough), and I am ALWAYS by myself. I would think I would fit the prototype of a target for whatever the scam-of-the-day happens to be.
I get offered drugs and women (and children...kind-of depressing...I am hoping it is not a vibe I am giving off) every night, but I politely decline, and keep on walking. I even got into my first fist fight last year late at night at Bambu (a really drunk obnoxious Brit...I think I won...not sure...I didn't see any marks on my face the next morning, and my fist hurt, so that is my story and I am sticking to it), and when the police arrived they just kind-of shushed me away. I can honestly say I have never had a problem with the Police.
I admit I may just have been lucky, and that may change the next time I am there (actually in a couple of weeks), but I am not sure why the police would go through this whole charade of having someone shake your hand, deposit drugs, and arresting you. They could just pick someone out at random, walk up to that person, throw drugs on the ground, say it is theirs, and arrest that person. Whether they put it in your hand, your pocket, or throw it on the ground, you know it is not yours, they know it is not yours, and there are no video cameras there. Bottom line, if you are selected for this type of operation there is nothing you can do about it.
I am not questioning the authenticity of the story (I am not a regular reader of DR1...but from some of the responses it sounds like the poster is a pretty good source), but I would argue there is a much greater chance of being seriously injured in a traffic accident (whether you are in a vehicle or not...you can get hit by a moto while walking on the sidewalk in Cabarete...I have even seen it happen!) than falling victim to this deal. Lets face it, Cabarete (or the DR in general) is not for the risk averse. And to be honest, this sounds pretty sophisticated for the folks I have run into there.