I would expect a standalone butcher shop to be responsive to questions just because they know you could just hit Costco if price was all you cared about. After all, they want you to come back. They may not refrigerate the bones and trimmings but they do have value. I have a neighbor who's family has been in the rendering business for 100 years and it's been pretty good to them.
The meat counter at Whole Foods said they would give me the trimmings off the grass-fed meat for nothing. How big a deal is rendering tallow? Pig fat I just threw in a crockpot and a few hours later it I had lard and crackings.
Wheat is the new tobacco. Spread the word.