some restaurants just dont get enough orders for milk to bother keeping stock...and some places (like chinese or thai places) dont have any milk on the premis since its not used in that food and azn ppl can be a bit more lactose intollerant...

i worked at an indian place....we had jugs and jugs of milk for making desserts...yet milk was never on the menu to order as is....i dont think anyones ever asked me for a glass of milk either...

the only place i see milk is at family type places (ie if the have a kids menu, your good)...order milk at a fancier place and they may pull there hair out for it... best advice is to pop into a cornerstore or even a mcds (ive never gotten an expired box from them) near your intended dining location and get a small box....just tell them you need a glass for it and that you bring your own since you can never find any (if they wanna fuss about it)...