That's a very interesting question, Marie! As you know, "best by" dates aren't actually mandatory, and its confusing because some things - like gelato! - really do diminish in quality after that time, while other - canned goods!? - could last unchanged for years.
Honestly, I'd say it depends on your relationship with the restaurant. If it's a nice place, you like it, maybe you've chatted with the manager before, then sure, I'd give them a friendly call. If it's a faceless national corporation, I probably wouldn't bother. And I'd also be mindful of the tone of my approach, to guard against the management's probably natural instinct that you're looking for a refund.
I'm sure this hasn't been particularly helpful, but it's a really interesting question. I wonder what others think.