I don't shoot professionally now, but we used to do a lot of tournaments and we constantly got questions. And it went so far as someone walking up to our photographer or our sales tables, and ask if we can configure their new xyz DSLR they bought so it can take pictures like we are taking. Seriously, there are people out there who have that much gawl. The reality with what we doing, is that it didn't matter what settings they made, their DSLR could shoot the high ISO range we were shooting, they didn't have the lenses we had, they didn't have the access we had to get close, and they also had no clue what they were doing. So in the end, I have always "tried" to answer truthfully and keep the answers quick. What usually happens is the answer would lead to more questions, and we were always very, very busy so eventually I'd have to just say, "look, I'd like to help you but I have a job to do and can't stand here talking".
The other thing I'll point out is that many of the folks I saw sporting a DSLR at an event were some of our biggest customers. While they had a nice camera, they didn't have the glass and experience... and they did appreciate photography.
The only things that really just annoyed me badly was when I was trying to do a large group picture, and people would try to "just get a shot" after I've done all the work to get the group posed the way I wanted. Of course while they were "just getting a shot", they caused have the group to now be looking at them instead of me. I had a guy one time come up and kneel in the floor beside my tripod so he could take a picture of every pose I did. I was using studio strobes, so I have no idea what his pictures looked like, but again... people have a lot of gawl.