Can I complain without sounding like a tattle-tale?
When I’m in a restaurant, often there’s a nearby conversation that’s several times louder than necessary. Is there any way to politely and tactfully ask them to be quieter? And whose responsibility is this: the restaurant’s, or those being disturbed? I don't want to offend the other group by telling them to keep it down, and then spend the rest of the night sitting near people I’ve just enraged.
Yes. But try to avoid confrontation...
By far the best solution is to discreetly ask the restaurant’s maitre d’ or head waiter to have a word with the loud table. While it may be tempting to approach such a group yourself, the results of this tactic (as you point out) can often be worse than the original problem. Another option is simply to ask that your group be reseated at a different table, away from the offending party. To some people, this approach may seem like a cop-out, but in fact, it may represent your path of least resistance to enjoying your evening out. Personally, I prefer taking the path of least resistance whenever possible.
Source: Post, Peter. "Etiquette at Work." Boston Globe 23 Oct. 2005.