This answer is penned by Deke who, in an earlier incarnation, was a waiter in a number of different restaurants, including a fancy resort at Denali National Park in Alaska.
Different restaurants, in my experience, have different policies concerning splitting entrees. If a restaurant "frowns on" a couple sharing one dinner, its policy is usually enumerated on the menu: "All diners must order an entrée." Or "Split-plate charge $8." Or something to that effect.
If there’s no mention of it on the menu, you can generally assume that it’s OK and there’s no extra charge. If you want to make absolutely sure, though, you can simply inquire of your server, "Do you guys mind if we split an entrée?"
I know that as a waiter, I loved people who split entrées. First of all, I never relished seeing food wasted (though as a starving dishwasher when I was much younger, that food didn’t go to waste, but don’t tell anyone) or charging people for food that they didn’t eat. And second, it allowed me to provide a little extra service, knowing that a portion of the money my diners saved on dinner, they could leave in the tip.
As an example of extra service, waiters often dish up the house salads that accompany entrées. Even at the "fancy" restaurant at Denali, we wait people scooped the salad with tongs out of a big plastic vat of iceberg lettuce, grated carrots, and red cabbage, then added a slice of tomato, a few croutons, and the dressing. So it was nothing for me to bring two slightly smaller plates of salad to people splitting a meal. And they each got a slice of tomato, croutons, and their own choice of dressing.
Beyond that, since I always made sure to have a strong rapport with the line cooks (in other words, when I got big tips, they got big tips), I could ask them to split a dinner for me. It was nothing for them to whack a steak or a piece of fish and a "baker" in half, then spoon up some vegetables on two plates.
Then, when I showed up with two plates -- with a big smile and just enough food to satisfy, but not stuff, lighter eaters -- for the price of one, my diners’ night was made. In fact, it often led to a deeper interaction between us, especially if they were package tourists who were mostly limited to talking to tour guides, bus drivers, and wait people and had lots of questions about the "Alaska life." It all added up to a memorable experience for my table and another big tip night for me and my boys in the kitchen.
All that said, I can tell you that not all wait people feel the way I did. I worked with some who wanted to crank up the bill as much as possible. But again, unless there’s a specific house policy that’s up to the wait person to enforce, there’s not only no harm in asking, but nine times out of ten, in my experience, you’ll get the meal that you want.
These days, as a restaurant patron, I occasionally split a meal with my bayyybee and I can always tell whether or not the wait person recognizes it as an opportunity. It matters little to me either way; we get the one split meal (even if it costs a little extra) and the only variable is in the size of the toke I leave.
