Part of this is navigating the laws. If you know what you're doing you can get that drink without ordering food. It's called "intent to dine". Ask questions about the food about the menu, in the meantime, order a drink. You'll get it. Then change your mind about the food. Easy. Establishments like Chili's or chain restaurants might have a "house rule" but that's it. Intent to dine, means when you walk into a place for drinks and the hostess says "5 for dinner"? And you answer, "no just drinks", you're doomed.

You can order a full bottle of wine for 1 person and even take the rest with you.

You can walk out of the hotel bar with your drink, most of the time people ask permission. The law is, you can't carry an open container outside the restaurant liquor license confines, a hostess, server, etc can carry it for you if you ask. But why did you ask in the first place? If you're that desperate to roam with an open beer/cocktail/wine, ask for a coffee cup...