This seems like a misguided effort to me. It may make you feel safer to arm your daughter with pepper spray and rohypnol detectors, but only a tiny minority of rapes involve strangers and/or date rape drugs. These things will do nothing to protect her from the most likely perpetrators, whose weapons include opportunity, plain old alcohol, and a culture that doesn't respect a woman's personal agency.I echoed my worry that this would create a false sense of complacency at feministing.com, and got several responses that arming yourself with this is better than nothing.
I'm not quite sure that I agree with that, however. There are a lot of obstacles to making this work. First of all, using this in the company of the guy who bought you a drink or at a frat party would probably feel awkward to most people. It's possible that it could be done discreetly if it ends up in the form of something like litmus paper, but I'm guessing that one couldn't test every drink they took every time they went out without people noticing. And for this to be effective, one would have to test every single drink - it's when your vigilance drops that your drink is going to be drugged after all. The places where I don't see this being used - when you invite a guy up for a drink after a date, or are at a small house party with a dozen of your close friends - is where it would be most useful. If you're planning to rape someone, you're going to create a situation in which your victim will not feel free to leave, let alone pull out a testing trip and accuse you of being a pre-rapist.
And, let's not forget the minescule likelihood that a "date rape drug" will be dropped into the drink of a rape victim. A study of 144 rape victims showed less than 5% of victims testing positive for any of the class of "date rape drugs," and this includes women who had voluntarily taken these drugs for either recreational or medicinal reasons. The study did find, however, that the majority of sexual assaults could be considered "drug-facilitated."
I would posit that the situations in which a woman would feel comfortable using a date rape drug detector would be the ones where it would be almost always unneeded, and that the situations in which a date rape drug detector could be most useful, it would not be used. Further, the ways that we can overcome these obstacles to the effective use of the detector - helping women work together to stay safe, empowering women to leave situations where they don't feel safe, and plain old self-defense - would be effective enough to make the detector moot.
On that subject, check out this conversation at Pandagon, about the situations in which self-defense training has helped people fend off attackers. There are a lot of good points about general feelings of safety, confidence, and the expected dynamics between men and women that can contribute to bad situations - or be takend advantage of by someone wishing to defend themself.