The WAPF has written about this a little bit, I forget where I saw it.
In general, ‘nicer’ restaurants tend to use better ingredients like butter rather than vegetable oils.
Some ethnic restaurants will use tropical oils. A friend mentioned the Ghanaian restaurant near him uses mostly palm oil.
Some Indian restaurants will use ghee (clarified butter) exclusively, or upon request.
Also, focusing on cuisine that emphasizes starches and/or dairy (I’m think Indian and French food) might minimize the veggie oils you eat. Obviously, avoiding things like deep fried food will help even in restaurants where PUFA is used.
I would frame conversations with the restaurant staff in terms of ‘Hey, I want the good stuff, and I’d be willing to pay a little more for it. So hook me up with the buttered scallops and extra virgin oil oil- I’ll make it worth your while.’ Better that than ‘Do you realize how awful and evil canola oil is?! Do you hate your customers?! Do you want them all to be sick and fat?!’ I find pulling someone toward the good stuff, rather than pushing away from the bad stuff, is more effective.