The problem is the explicit link between drinking and rape. Getting steaming increases the risk of practically every negative outcome you can imagine — being run over or mugged, getting into a fight, contracting an STD, depression, getting sacked from your job the next morning, losing your housekeys. Anything, really. And men are every bit as vulnerable, sometimes more so.
The advert confuses two separate warnings. The first should be addressed to young people of all genders and it should read: don't get shitfaced, folks, bad things can happen to you. The police did not issue that advert. The second is addressed to women, and it warns them that if they get drunk, they are exposing themselves to one particular risk — being raped. The formula is 'Doing X (ie, drinking excessively) leads to Y (being raped).' That's victim blaming.
Rape happens for one reason only — because rapists make it happen. Perhaps it's true that rapists look for easy victims, but what is the logic of the police campaign? If there's a rapist in the bar, and I'm stone cold sober, then yes I've reduced my chance of being raped — but every other potential victim's odds have become a little worse. If we accept the idea that rapists prey on drunk women (which is only part of it, and excludes spiking drinks, and so on), then the only way for us women in the bar to avoid this particular rapist is if we all remain absolutely sober. That's the message of the advert to women: Don't have fun, don't lose control even for one night, remain vigilant (and scared) at all times because you are a woman — and if you should neglect this advice, well, the consequences are your own fault.
The only way to prevent rape is to prevent rapists.
Any kind of advertising has to put across a message within a couple of seconds because that's the attention span of your average reader. Let's say you were asked to come up with a poster campaign to warn women about the increased risk of getting raped when very drunk, what would be your approach? Bear in mind that the campaign is targeted at young women in places like night clubs or pubs.