I have seen several things changed as a result of my shopping....
* A host station was moved to make an entryway wider at a restaurant after I reported two near collisions between guests and waitstaff.
* Several casino bathroom "issues" were resolved.
I suspect that my reports simply drew attention to obvious problems and that they just needed to be pointed out to upper-management to get them resolved. These were changes that posed liability to the company and did not take major policy changes or debates.
However, if I point out an "issue" that is not a clear liability issue or something for which one person might think less important than what I think, the suggestion might get discussed internally and eventually enacted, or simply rejected. It's not like I have the clout to change policy.
Hard work builds character and homework is good for your soul.