I have to disagree with several of the markers in the OP;
Bar girls often drink alcohol, whereas "good" Asian girls hardly ever drink, and certainly don't drink to get drunk. EVEN good girls will have A drink.
Bar girls will often say that they're unemployed, or have a home business. Sari-sari stores are a common 'home business, so that is not a good marker.
Bar girls tend to live in the larger cities with big entertainment industries, e.g. Bangkok, Pattaya, Cebu, Manila. This is a very sweeping generalization, and not true. Pattaya and Angeles City would be flag raisers, but not Manila, or Cebu.
Bar-girls usually work the night-shift, but to hide this, they will say they work in a call-centre [which has a high night shift duty roster] - ask for photos of her at work.
Bar-girls will have poorer English skills.
Bar-girls will wear more revealing outfits, and often have tattoos. If their photos appear sexy then that is a BIG flag.
Bar-girls won't discuss their work.
Bar-girls will use bar slang.
Bar-girls will disappear for periods of time - they have a client who has paid for the absence from the bar.
Bar-girls are more obsessed with gadgets and brand-names. If she has an iPhone 5, or a LV hand-bag then chances are it was gift from a client.
Bar-girls will flirt more and talk more abut sex.
Bar-girls will often ask for money.