Xanax is not a date rape drug and it is not illegal. I guess if you could get someone to ram down 20 of them it might do something, but it is not in the class like Rohypnol and not a hypnotic.
Neith Xanax nor Valium are sleeping medications.
Both are controlled substances in Thailand and good for time in the clink if caught. Not quite meth but not legal without a prescription. All you need is a Thai cop making a point. Or seeking a bribe.
People who think they can sleep on Xanax are benefiting from the placebo effect, though it is not particularly dangerous. It is not a hypnotic (the term for a sleeping medication)
Xanax is prescribed for anxiety, so is Ativan, and so is Valium. They differ mostly by the duration of action, Valium being very long, Xanax very short lasting. For anxiety. Panic attack, that sort of disorder.
These pills do not cost much from an actual pharmacy where you live, so why not ask your family doctor for a few Triazolam (Halcion) which actually is specific for helping you sleep?
1/4 mg will put you out to combat jet lag, it is very short duration which is what you want, and you wake up naturally without a benzo hangover. Are people afraid to ask a GP for something as routine as this? Mine will give me 20 at a time though I only use 2 per trip.