A quick anecdote - my wife used to volunteer at a clinic in Chinatown. The doctor always get invites for lunch/dinner from medicine companies and she'd sometimes invite my wife to attend. I was extended an invite to one of them (the doctor knows me via my wife). It was hosted by a rep from Sanofi for the staff of the entire clinic (about 6 people) plus their SOs (including myself and the doctor's husband). There were a total of ~10 people at the dinner and the doctor gets to pick the restaurant so she picked one of the most expensive hotpot restaurants in Chinatown. We ordered lots of grade A beef slices and other expensive goodies. The rep, who is white, curried favors with the doc and the nurses/staff members all evening (to the point that I felt cringe at one point when she says something like this to an asian nurse, "I really like your Asian skin and hair; it's so smooth and glowing"). My estimate is that the dinner bill came out to at least $2000. That dinner, according to the doctor, happens every year with this particular company. Of course, I had to sign on a sheet (roll-call if you will) to acknowledge that I attended the dinner (I presume it's for the rep to reclaim expenses). I can only imagine how much/many drugs from Sanofi that the doctor is prescribing to her patients throughout the year.
Another anecdote - my host-family mom is a psychiatrist (the doctor type; not the other psychiatrist kind). She worked for a private mental institution near Philadelphia. There, they have about 20 mentally-challenged patients, 4-5 nurses and my host-family mom. I have accompanied her to there a couple of times and spent ~6 hours while she was touring and meeting with the patients. Both times, a rep from a medicine company brought lunch for the host-family mom and all the staff. Once was just pizza. Another time was some sort of sandwich and stuff. According to my host-family mom, that's pretty typical and they have about two or so such lunch from medicine company reps every week.