In the business world, the guest is free to order anything they want in terms of food. And the protocol is
But it's different with booze, appetizers and dessert. Unlike the entree, there's no assumption with these, so to make it work, the host simply takes the lead and it's polite for the guest to follow suit (if they want that). I don't order booze at lunch, so when asked by the server what we'd like to drink, I violate the protocol of guest orders first and I just speak up "I'd like iced tea" - and guest knows to order a soft drink, not booze. And if that's fine with me, I'll make a point and specifically say, "Feel free to order ________, I'm just a iced tea drinker." Same with appetizers and dessert (neither do I order at lunch). I just take the lead: "I'm not a dessert person (because I'm not) but feel free to order dessert." But for the entree, yeah the guest is free to order anything on the menu and it's not at all inappropriate to order an expensive (even most expensive) item - no problem (of course, I'm not personally paying for this, the company is).
In dating, thinking WAY back when I was dating. It kind of depended on the situation and the restaurant - but yeah, she's welcome to order whatever she wants; my job is to please, honor, take care of her. A fancy place at dinner kind of assumed to include wine, appetizer and dessert. Hey, a guy is winning her over! Don't be cheap!!!! If you take this beautiful lady to a grand place, you are prepared for a big bill (and that's what you'll get) - she's worth it, and a lot more.
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