do you mean, while volunteering or before you get to med school? I shadowed a orthopod mwf in his office, and on t, th for any scheduled surgeries, I thought it was a good balance of seeing the daily side of practice and i got to scrub in on lots of surgeries, which i really liked.
Around NO, volunteering strictly through a hospital, there are lots of regulations especially with all the HIPAA laws, I work in a research lab at a hospital, and during the vol. orientation, you were not to talk to doctors, not ask patients about their conditions or treatments, it sounded very restrictive and that you could learn little from this.
When i shadowed that orthopod, the first day, his nurse had me sign a HIPAA waiver form stating that i would not discuss patients info with anyone else, There was no paperwork for me to go into the OR, althought i think this had to do with it being a rural hospital and that this doctor allowed students to follow him often.