I’m not sure how useful this would be. How many women are actually going to dip their finger into a drink every time they look away from it? I approve of the sentiment, but I doubt it would help.
Especially if it's not their first drink. Although this is a good thing on the "every little bit helps" principle, the "feminist" critics are correct that alcohol is a much bigger factor in both rape situations and "sex you regret afterward" situations.
It's not smart to get impaired in situations where you think you are vulnerable.