Glucose pills are available over the counter at most pharmacies for as low as $6. Diabetic hypoglycemia is a very serious condition has the potential to leave permanent damage or even prove fatal if left untreated. Glucose pills are an easy, cheap and effective way of raising the blood sugar of a diabetic in distress.

More serious cases of hypoglycemia can have all the signs of drunkenness- slurred speech, lack of coordination, aggressive behavior, ect. Next time you run into someone who appears to be drunk, they may actually be in a hypoglycemic state. Check their skin; if the problem's hypoglycemia, the skin will be pale, cold and clammy, and they'll be sweating.

Is there any danger if someone takes the pills and turns out not to be hypoglycemic?

Glucose pills generally are no more dangerous than, say, eating a packet of sugar. Glucose pills consist primarily of monosaccharide sugar, which is simply a type of sugar that is more rapidly absorbed into the body than other sugars. The advantage glucose pills have over simply eating something sugary is that glucose pills will start taking effect immediately, while sugary food needs to be broken down before it can be absorbed.
The only real "danger" to glucose pills, at least that I'm aware of, is that they can't be used on people of reduced consiousness levels or on particularly combative people (hypoglycemia can sometimes cause aggression or violent behavior) because of the risk of choking. There are glucose gels for this, but I don't know anything about price or otc availibility for the gel variant.

I guess this falls under the "Its a nice thing to have handy, but if something gets messed up, DONT GET CAUGHT"

Yeah if someone is combative or unconciousness don't just shove one down their throat or nothing they'll just choke and anyways if it's progressed far enough that they're losing conciousness they need medical attention. If they're still verbally responsive, though, it should be fine.
Obviously this isn't some sort of miracle panacea but it can help a lot in the right situations. I just figured that since diabeties is relatively common it wouldn't be a bad thing to carry around.

I agree. Im borderline diabetic, myself. Im not at the point where i could go into a diabetic coma, but I could see where it could be useful.